# Milkweed USA: full text corpus > A free field guide to every milkweed species in the United States: identification, range maps, bloom times, seed germination and monarch habitat guidance. Licence: CC BY 4.0. Attribution: Milkweed USA (https://milkweedusa.com). Generated 2026-08-01. 137 documents. --- # Antelope Horns (Asclepias asperula) > A low, sprawling clump of arching stems topped by softball-sized globes of green flowers with maroon centers, blooming very early on limestone and caliche soils. In Texas and New Mexico it is the plant that meets the first northbound monarchs of the year. Source: https://milkweedusa.com/species/antelope-horns/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A low, sprawling clump of arching stems topped by softball-sized globes of green flowers with maroon centers, blooming very early on limestone and caliche soils. In Texas and New Mexico it is the plant that meets the first northbound monarchs of the year. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias asperula (Decne.) Woodson | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Antelope Horns, Spider Milkweed, Green-flowered Milkweed | | Status | Native | | Height | 1 ft–2 ft | | Spread | 1.5 ft–3 ft | | Flower color | green, cream, maroon | | Bloom period | March to July | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 5-9 | | Leaf arrangement | alternate | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 5 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, Colorado, Kansas, Nebraska, New Mexico, Nevada, Oklahoma, Texas, Utah | ## Identification - Flowers in tight spherical clusters, pale green with dark red-purple hoods. No other milkweed in its range looks like this. - Stems sprawl outward and curve upward rather than standing straight. - Leaves are long, narrow and often folded lengthwise along the midrib. - Curved, upward-pointing pods gave the plant its name. ## Ecology Critically timed rather than merely abundant: it is in full leaf in March and April when monarchs arrive in Texas from Mexico, making it a keystone host for the first generation of the year. Also heavily used by queen butterflies. ## Growing Demands lean, alkaline, sharply drained soil and full sun; it rots quickly in rich beds or irrigated lawns. Direct-sow into gravelly ground, because the taproot resents transplanting. Goes dormant by late summer. ## Cautions One of the more toxic species to livestock, historically responsible for sheep losses on overgrazed range. ## Questions **When do antelope horns bloom in Texas?** Typically March through May, with a possible second flush after summer rain. That early bloom is what makes it so important to the first northbound monarch generation. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21143-2 - GBIF: https://www.gbif.org/species/8683730 - iNaturalist: https://www.inaturalist.org/taxa/62298 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_asperula - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20asperula.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20asperula ## Photographs - Asclepias asperula - Antelope Horns (Wing-Chi Poon, CC BY-SA 2.5): https://commons.wikimedia.org/wiki/File:Asclepias_asperula_-_Antelope_Horns.jpg - Asclepias asperula 1 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_asperula_1.jpg - Asclepias asperula 2 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_asperula_2.jpg - Asclepias asperula 3 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_asperula_3.jpg - Asclepias asperula 4 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_asperula_4.jpg - Asclepias asperula 5 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_asperula_5.jpg - Asclepias asperula 6 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_asperula_6.jpg - Asclepias asperula 9 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_asperula_9.jpg ## How to cite Milkweed USA. (2026). Antelope Horns (Asclepias asperula). https://milkweedusa.com/species/antelope-horns/ --- # Aquatic Milkweed (Asclepias perennis) > A small, soft, white-flowered milkweed of southern swamps and river floodplains that will grow in standing water and in shade, two things no other milkweed manages. Its seeds are unique in the genus: they have no silky floss. Source: https://milkweedusa.com/species/aquatic-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A small, soft, white-flowered milkweed of southern swamps and river floodplains that will grow in standing water and in shade, two things no other milkweed manages. Its seeds are unique in the genus: they have no silky floss. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias perennis Walter | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Aquatic Milkweed, Swamp White Milkweed, Thin-leaved Milkweed | | Status | Native | | Height | 1 ft–3 ft | | Spread | 1 ft–2 ft | | Flower color | white, pink | | Bloom period | May to September | | Light | Part shade, Shade, Full sun | | Soil moisture | Wet | | USDA zones | 6-9 | | Leaf arrangement | opposite | | Leaf shape | lanceolate | | Sap | Milky latex | | Root system | Fibrous, clump-forming and easy to move | | Seed stratification | None required | | Monarch value (0-5) | 4 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 3 | | US states recorded | Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Missouri, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia | ## Identification - Grows in genuinely wet ground, often with its feet in water. - Small white flowers, sometimes pink-flushed, in delicate clusters. - Thin, soft, pointed leaves; the whole plant is fine-textured. - Seeds lack the parachute of silk found in every other milkweed. ## Ecology The key monarch host in southeastern floodplain forest and cypress swamp, and one of the few milkweeds that stays soft and edible through the humid southern summer. ## Growing Superb for rain gardens, pond edges and shaded wet spots in the Southeast. Needs no stratification: sow fresh seed and it germinates in days. Blooms the first year. ## Cautions Standard milkweed cautions. ## Questions **What milkweed grows in Florida?** Aquatic milkweed (A. perennis) for wet and shaded sites, pinewoods milkweed (A. humistrata) and butterfly weed for dry sand, and swamp milkweed in the north of the state. Florida gardeners should avoid tropical milkweed, which breeds monarchs year-round and spreads OE parasites. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30270360-2 - GBIF: https://www.gbif.org/species/3170346 - iNaturalist: https://www.inaturalist.org/taxa/120152 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_perennis - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20perennis.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20perennis ## Photographs - Coastal Georgia Botanical Gardens, Swamp Milkweed Asclepias perennis (Michael Rivera, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Coastal_Georgia_Botanical_Gardens,_Swamp_Milkweed_Asclepias_perennis.jpg - Asclepias perennis 222094081 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_perennis_222094081.jpg - Asclepias perennis 222094111 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_perennis_222094111.jpg - Asclepias perennis 222093949 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_perennis_222093949.jpg - Asclepias perennis 52080041 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_perennis_52080041.jpg - Asclepias perennis 52080032 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_perennis_52080032.jpg - Asclepias perennis 52080068 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_perennis_52080068.jpg - Asclepias perennis 52080048 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_perennis_52080048.jpg ## How to cite Milkweed USA. (2026). Aquatic Milkweed (Asclepias perennis). https://milkweedusa.com/species/aquatic-milkweed/ --- # Balloon Plant (Gomphocarpus physocarpus) > Not a true milkweed but a close African relative, grown everywhere for its extraordinary inflated, bristly, balloon-like pods. Monarchs will use it as a host, and in frost-free regions it raises exactly the same winter-breeding concerns as tropical milkweed. Source: https://milkweedusa.com/species/balloon-plant/ Licence: CC BY 4.0 (Milkweed USA) ## Summary Not a true milkweed but a close African relative, grown everywhere for its extraordinary inflated, bristly, balloon-like pods. Monarchs will use it as a host, and in frost-free regions it raises exactly the same winter-breeding concerns as tropical milkweed. ## Key facts | Field | Value | | --- | --- | | Scientific name | Gomphocarpus physocarpus E. Mey. | | Genus | Gomphocarpus | | Family | Apocynaceae | | Common names | Balloon Plant, Hairy Balls, Swan Plant, Balloon Cotton Bush | | Status | Not native to the United States | | Height | 3 ft–6 ft | | Spread | 2 ft–4 ft | | Flower color | white, cream | | Bloom period | May to October | | Light | Full sun | | Soil moisture | Average | | USDA zones | 8-11 | | Leaf arrangement | opposite | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Fibrous, clump-forming and easy to move | | Seed stratification | None required | | Monarch value (0-5) | 3 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Alabama, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, South Carolina, Texas | ## Identification - Pods are pale green spheres covered in soft bristles, unmistakable and unlike any Asclepias. - Small waxy white flowers hanging in nodding clusters. - Tall, shrubby, softly hairy stems with narrow willow-like leaves. ## Ecology Monarch larvae develop successfully on it, and it is widely used in butterfly houses and school rearing projects. It is native to southern Africa, not North America. ## Growing Easy from seed with no stratification and fast enough to flower in one season, so it is best grown as an annual in cold regions. In zones 9 and warmer, cut it back through winter or use a native species instead. ## Cautions Non-native. In frost-free regions its evergreen growth encourages winter monarch breeding and OE parasite build-up, exactly as tropical milkweed does. ## Questions **Is balloon plant the same as milkweed?** It is a close relative in the same subfamily, not a true Asclepias. Monarch caterpillars do eat it, but it is native to southern Africa. In frost-free regions the same winter-breeding cautions apply as for tropical milkweed. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:97670-1 - GBIF: https://www.gbif.org/species/3170326 - iNaturalist: https://www.inaturalist.org/taxa/281273 - Wikipedia: https://en.wikipedia.org/wiki/Gomphocarpus_physocarpus - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Gomphocarpus%20physocarpus ## Photographs - Gomphocarpus physocarpus flower buds1 (14439930407) (Harry Rose from South West Rocks, Australia, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Gomphocarpus_physocarpus_flower_buds1_(14439930407).jpg - Gomphocarpus physocarpus flower4 (14626324605) (Harry Rose from South West Rocks, Australia, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Gomphocarpus_physocarpus_flower4_(14626324605).jpg - Gomphocarpus physocarpus habit4 (14603314966) (Harry Rose from South West Rocks, Australia, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Gomphocarpus_physocarpus_habit4_(14603314966).jpg - Balloon Plant photographed in Blyde River Near Hoedspruit: Blyde river alongside floodplain. (Wynand Uys, CC BY 4.0): https://www.inaturalist.org/observations/10847450 - Balloon Plant photographed in WHVF+F66, San Luis de Cañete 15720, Perú (Public domain (CC0), CC0): https://www.inaturalist.org/observations/199189628 - Balloon Plant photographed in Cacadu, ZA-EC, ZA (Henry de Lange, CC BY 4.0): https://www.inaturalist.org/observations/12454057 - Balloon Plant photographed in Glenroy Place, Port Elizabeth, EC, ZA (Andrew Gillespie, CC BY-SA 4.0): https://www.inaturalist.org/observations/104447206 - Balloon Plant photographed in Stellenbosch, WC, ZA (Dave Richardson, CC BY 4.0): https://www.inaturalist.org/observations/73022814 ## How to cite Milkweed USA. (2026). Balloon Plant (Gomphocarpus physocarpus). https://milkweedusa.com/species/balloon-plant/ --- # Bract Milkweed (Asclepias brachystephana) > A low desert grassland milkweed with narrow folded leaves and dense clusters of small dusky purple flowers held tight in the leaf axils, common on caliche flats in New Mexico and west Texas. Source: https://milkweedusa.com/species/bract-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A low desert grassland milkweed with narrow folded leaves and dense clusters of small dusky purple flowers held tight in the leaf axils, common on caliche flats in New Mexico and west Texas. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias brachystephana Engelm. ex Torr. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Bract Milkweed, Short-crown Milkweed | | Status | Native | | Height | 6 in–1.5 ft | | Spread | 1 ft–2 ft | | Flower color | maroon, purple | | Bloom period | April to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 6-10 | | Leaf arrangement | opposite | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 2 | | US states recorded | Arizona, New Mexico, Texas | ## Identification - Small purple-maroon flowers in compact axillary clusters. - Narrow leaves, often folded along the midrib and grayish. - Low sprawling habit on hard calcareous desert soils. ## Ecology A widespread Chihuahuan Desert host used by monarchs and queens during migration. ## Growing Rarely cultivated. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94136-1 - GBIF: https://www.gbif.org/species/3170258 - iNaturalist: https://www.inaturalist.org/taxa/158733 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_brachystephana - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20brachystephana.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20brachystephana ## Photographs - Asclepias brachystephana - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_brachystephana_-_Flickr_-_aspidoscelis.jpg - Asclepias brachystephana - Flickr - aspidoscelis (1) (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_brachystephana_-_Flickr_-_aspidoscelis_(1).jpg - Asclepias brachystephana - Flickr - aspidoscelis (2) (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_brachystephana_-_Flickr_-_aspidoscelis_(2).jpg - Bract Milkweed photographed in Pecos County, TX, USA (Michelle W. （鍾偉瑋）, CC BY 4.0): https://www.inaturalist.org/observations/126146369 - Bract Milkweed photographed in Brewster, Texas, United States (Reid Hardin, CC BY 4.0): https://www.inaturalist.org/observations/118716880 - Bract Milkweed photographed in Big Bend National Park, Brewster County, US-TX, US (Sam Kieschnick, CC BY 4.0): https://www.inaturalist.org/observations/4252505 - Bract Milkweed photographed in Jeff Davis County, TX, USA (Joseph Aubert, CC BY 4.0): https://www.inaturalist.org/observations/298313092 - Bract Milkweed photographed in Midland, TX 79705, Midland, TX, US (samlutfy, CC BY 4.0): https://www.inaturalist.org/observations/12666898 ## How to cite Milkweed USA. (2026). Bract Milkweed (Asclepias brachystephana). https://milkweedusa.com/species/bract-milkweed/ --- # Broadleaf Milkweed (Asclepias latifolia) > Thick, almost circular leaves stacked up a stout stem like a pile of green plates, with flower clusters tucked into the leaf axils. A tough, deeply rooted southern plains species that thrives where summer means 100°F and no rain. Source: https://milkweedusa.com/species/broadleaf-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary Thick, almost circular leaves stacked up a stout stem like a pile of green plates, with flower clusters tucked into the leaf axils. A tough, deeply rooted southern plains species that thrives where summer means 100°F and no rain. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias latifolia (Torr.) Raf. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Broadleaf Milkweed, Corn-kernel Milkweed, Broadleaf Milkvine | | Status | Native | | Height | 1 ft–3 ft | | Spread | 1.5 ft–4 ft | | Flower color | green, cream | | Bloom period | May to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 5-9 | | Leaf arrangement | opposite | | Leaf shape | orbicular | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, Colorado, Kansas, Nebraska, New Mexico, Nevada, Oklahoma, Texas, Utah, Wyoming | ## Identification - Leaves are very broad, blunt-tipped and often wider than they are long, clasping the stem closely. - Flower clusters sit in the leaf axils rather than crowning the plant. - Stems are stout and unbranched, giving a stiff, architectural look. ## Ecology Its big leaves make it a productive monarch host on the southern plains, where it is one of the few milkweeds with real leaf area. Grazing animals avoid it, so it persists on heavily used rangeland. ## Growing Extremely drought-tolerant and long-lived, but rhizomatous and considered a rangeland weed by ranchers. Rarely offered in the nursery trade. ## Cautions Toxic to livestock, and unpalatable enough that it increases on overgrazed land. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94386-1 - GBIF: https://www.gbif.org/species/3170304 - iNaturalist: https://www.inaturalist.org/taxa/62296 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_latifolia - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20latifolia.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20latifolia ## Photographs - Asclepias latifolia flower (Jackvanschaik, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_latifolia_flower.jpg - Asclepias latifolia plant (Jackvanschaik, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_latifolia_plant.jpg - Asclepias latifolia (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_latifolia.jpg - Asclepias latifolia - 49961588466 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_latifolia_-_49961588466.jpg - Asclepias latifolia - 49961591761 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_latifolia_-_49961591761.jpg - Broadleaf Milkweed photographed in Presidio County, US-TX, US (Alison Northup, CC BY 4.0): https://www.inaturalist.org/observations/36309572 - Broadleaf Milkweed photographed in Lincoln, Colorado, United States (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/59850649 - Broadleaf Milkweed photographed in Lubbock Lake Landmark, Lubbock, TX, USA (Catherine C. Galley, CC BY 4.0): https://www.inaturalist.org/observations/124206763 ## How to cite Milkweed USA. (2026). Broadleaf Milkweed (Asclepias latifolia). https://milkweedusa.com/species/broadleaf-milkweed/ --- # Butterfly Weed (Asclepias tuberosa) > The one milkweed almost everyone recognizes: flat-topped clusters of brilliant orange flowers on a stiff, hairy, knee-high clump. It is the most garden-worthy species in the genus: tidy, drought-proof, long-lived and unbothered by anything except wet soil. It is also the odd one out in the family, with alternate leaves and watery rather than milky sap. Source: https://milkweedusa.com/species/butterfly-weed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary The one milkweed almost everyone recognizes: flat-topped clusters of brilliant orange flowers on a stiff, hairy, knee-high clump. It is the most garden-worthy species in the genus: tidy, drought-proof, long-lived and unbothered by anything except wet soil. It is also the odd one out in the family, with alternate leaves and watery rather than milky sap. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias tuberosa L. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Butterfly Weed, Butterfly Milkweed, Orange Milkweed, Pleurisy Root, Chigger Flower | | Status | Native | | Height | 1 ft–3 ft | | Spread | 1 ft–2 ft | | Flower color | orange, yellow, red | | Bloom period | May to September | | Light | Full sun | | Soil moisture | Dry, Average | | USDA zones | 3-9 | | Leaf arrangement | alternate | | Leaf shape | lanceolate | | Sap | Clear (unusual in the genus) | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 5 | | Nectar value (0-5) | 5 | | US states recorded | Alabama, Arkansas, Arizona, Colorado, Connecticut, District of Columbia, Delaware, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Mississippi, North Carolina, North Dakota, Nebraska, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Vermont, Wisconsin, West Virginia, Wyoming | ## Identification - Sap is clear or barely cloudy. It is the only common North American milkweed that does not bleed white latex when a leaf is pulled. - Leaves are alternate and stalkless, not paired opposite each other as in most milkweeds. - Stems and leaves are noticeably rough-hairy; the whole plant feels sandpapery. - Flowers range from yellow through pumpkin to nearly scarlet, often varying between plants in a single population. ## Ecology Butterfly weed is a nectar powerhouse. The shallow flowers are worked by fritillaries, swallowtails, hairstreaks, bumble bees and hundreds of small native bees. Monarchs lay on it readily, though the narrow leaves support fewer caterpillars per plant than the big-leaved species. Its clear sap is also lower in cardenolides than most milkweeds, which makes it a milder host. ## Growing Give it sun and sharp drainage and it will outlive you; give it clay that stays wet in winter and it will rot. The deep taproot means it hates being moved once established, so plant it small or sow it in place. It emerges very late in spring, so mark the spot to avoid digging it up. No staking, no dividing, no feeding. ## Cautions Cardiac glycosides are present but low. Livestock avoid it. The old herbal name "pleurisy root" reflects historical medicinal use, not a safety endorsement. Do not ingest it. ## Questions **Is butterfly weed the same as milkweed?** Yes. Butterfly weed (Asclepias tuberosa) is one of roughly 75 milkweed species in North America. The confusion comes from its clear sap and orange flowers, which look nothing like the pink drooping umbels of common milkweed. **Why is my butterfly weed not coming up in spring?** It is famously the last perennial in the bed to break dormancy, often four to six weeks after everything else. In cold regions it may not appear until late May or June. Do not dig, do not water heavily, and do not give up before midsummer. **Can I move an established butterfly weed?** Rarely with success. The taproot can go two to three feet down and resents disturbance. If you must move it, do so in early spring as growth begins, dig far wider and deeper than feels reasonable, and expect a lost season. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94704-1 - GBIF: https://www.gbif.org/species/3170305 - iNaturalist: https://www.inaturalist.org/taxa/47912 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_tuberosa - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20tuberosa.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20tuberosa ## Photographs - Asclepias tuberosa 001 (H. Zell, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_tuberosa_001.JPG - Asclepias tuberosa bud (Rob Duval, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_tuberosa_bud.jpg - Asclepias tuberosa BUTTERFLY MILKWEED (3194738925) (Frank Mayfield from Chicago area, USA, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_tuberosa_BUTTERFLY_MILKWEED_(3194738925).jpg - Asclepias tuberosa BUTTERFLY MILKWEED (3194741429) (Frank Mayfield from Chicago area, USA, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_tuberosa_BUTTERFLY_MILKWEED_(3194741429).jpg - Asclepias tuberosa BUTTERFLY MILKWEED (3195582394) (Frank Mayfield from Chicago area, USA, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_tuberosa_BUTTERFLY_MILKWEED_(3195582394).jpg - Asclepias tuberosa Hello Yellow 2zz (Photo by David J. Stang, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_tuberosa_Hello_Yellow_2zz.jpg - Asclepias tuberosa in La Jaysinia (1) (Krzysztof Golik, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_tuberosa_in_La_Jaysinia_(1).jpg - Asclepias tuberosa in La Jaysinia (2) (Krzysztof Golik, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_tuberosa_in_La_Jaysinia_(2).jpg ## How to cite Milkweed USA. (2026). Butterfly Weed (Asclepias tuberosa). https://milkweedusa.com/species/butterfly-weed/ --- # California Milkweed (Asclepias californica) > A gorgeous, entirely white-woolly California endemic whose deep wine-red flowers hang in heavy nodding clusters against silver foliage. It looks like a plant designed rather than evolved. Source: https://milkweedusa.com/species/california-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A gorgeous, entirely white-woolly California endemic whose deep wine-red flowers hang in heavy nodding clusters against silver foliage. It looks like a plant designed rather than evolved. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias californica Greene | | Genus | Asclepias | | Family | Apocynaceae | | Common names | California Milkweed, Round-hooded Milkweed | | Status | Native | | Height | 1 ft–3 ft | | Spread | 1.5 ft–3 ft | | Flower color | maroon, purple | | Bloom period | April to July | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 8-10 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 3 | | US states recorded | California | ## Identification - Entire plant thickly felted in white wool, giving a silver-gray appearance. - Flowers deep maroon to dusty purple-red, in large drooping clusters. - Stems sprawl and arch outward from a woody crown. - Chaparral, oak woodland and grassland slopes below 7,000 feet. ## Ecology An important western monarch host in the California foothills, blooming before the summer dry season arrives. ## Growing Superb in a dry California garden but resents summer water once dormant. Sharp drainage, full sun, and no irrigation after June. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21153-2 - GBIF: https://www.gbif.org/species/3170236 - iNaturalist: https://www.inaturalist.org/taxa/51272 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_californica - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20californica.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20californica ## Photographs - Asclepias californica (172276296) (Joe Decruyenaere, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_californica_(172276296).jpg - Asclepias californica, California Milkweed (glmory, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_californica,_California_Milkweed.jpg - Asclepias californica, California milkweed (glmory, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_californica,_California_milkweed.jpg - Asclepias californica, California milkweed 2 (glmory, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_californica,_California_milkweed_2.jpg - Asclepias californica (Eric Hunt, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_californica.jpg - Asclepias sp. flowers (Marshal Hedin) (Marshal Hedin, CC BY-SA 2.5): https://commons.wikimedia.org/wiki/File:Asclepias_sp._flowers_(Marshal_Hedin).jpg - Asclepias sp. (Marshal Hedin) (Marshal Hedin, CC BY-SA 2.5): https://commons.wikimedia.org/wiki/File:Asclepias_sp._(Marshal_Hedin).jpg - California Milkweed photographed in Moorpark, CA, US (klicklo, CC BY 4.0): https://www.inaturalist.org/observations/283479707 ## How to cite Milkweed USA. (2026). California Milkweed (Asclepias californica). https://milkweedusa.com/species/california-milkweed/ --- # Carolina Milkweed (Asclepias cinerea) > A wiry, thread-leaved coastal plain milkweed carrying a few widely spaced, unusually elegant ash-mauve flowers that seem to hover in mid-air on hair-fine stalks. Source: https://milkweedusa.com/species/carolina-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A wiry, thread-leaved coastal plain milkweed carrying a few widely spaced, unusually elegant ash-mauve flowers that seem to hover in mid-air on hair-fine stalks. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias cinerea Walter | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Carolina Milkweed, Ash-colored Milkweed | | Status | Native | | Height | 1 ft–2.5 ft | | Spread | 8 in–1.3 ft | | Flower color | mauve, gray | | Bloom period | May to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 8-9 | | Leaf arrangement | opposite | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 2 | | US states recorded | Alabama, Florida, Georgia, Mississippi, North Carolina, South Carolina | ## Identification - Very fine, almost invisible flower stalks, so the blooms appear to float. - Flowers pale gray-lavender, sparse, in small open clusters. - Thread-like opposite leaves on a slender stem in dry sandy pineland. ## Ecology A fire-maintained sandhill species of the Carolinas, Georgia and Florida panhandle. ## Growing Rare in cultivation; requires sand, sun and lean soil. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94162-1 - GBIF: https://www.gbif.org/species/3170337 - iNaturalist: https://www.inaturalist.org/taxa/158734 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_cinerea - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20cinerea.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20cinerea ## Photographs - Asclepias cinerea by Siddarth Machado (Siddarth Machado, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_cinerea_by_Siddarth_Machado.jpg - Asclepias cinerea 81678256 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_cinerea_81678256.jpg - Asclepias cinerea 81675172 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_cinerea_81675172.jpg - Asclepias cinerea 81675244 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_cinerea_81675244.jpg - Asclepias cinerea 81675303 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_cinerea_81675303.jpg - Asclepias cinerea 81675464 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_cinerea_81675464.jpg - "Carolina milkweed habitat" by Scott Allen Davis (Scott Allen Davis, CC BY 4.0): https://commons.wikimedia.org/wiki/File:%22Carolina_milkweed_habitat%22_by_Scott_Allen_Davis.jpg - Carolina milkweed leaves by Scott Allen Davis (Scott Allen Davis, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Carolina_milkweed_leaves_by_Scott_Allen_Davis.jpg ## How to cite Milkweed USA. (2026). Carolina Milkweed (Asclepias cinerea). https://milkweedusa.com/species/carolina-milkweed/ --- # Clasping Milkweed (Asclepias amplexicaulis) > Unmistakable once you have seen it: wavy-edged blue-green leaves clasping directly around the stem, and a single long bare stalk lifting one rounded cluster of dusty pink-green flowers well clear of the foliage. Source: https://milkweedusa.com/species/clasping-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary Unmistakable once you have seen it: wavy-edged blue-green leaves clasping directly around the stem, and a single long bare stalk lifting one rounded cluster of dusty pink-green flowers well clear of the foliage. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias amplexicaulis Sm. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Clasping Milkweed, Blunt-leaved Milkweed, Sand Milkweed | | Status | Native | | Height | 1.5 ft–3 ft | | Spread | 1 ft–2 ft | | Flower color | pink, green, mauve | | Bloom period | May to July | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 3-9 | | Leaf arrangement | opposite | | Leaf shape | clasping | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Alabama, Arkansas, Connecticut, District of Columbia, Delaware, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Michigan, Minnesota, Missouri, Mississippi, North Carolina, Nebraska, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Virginia, Wisconsin, West Virginia | ## Identification - Leaf bases wrap around the stem with no stalk at all. - Leaf margins are strongly wavy and the surface is smooth and waxy. - One flower cluster per stem on a long naked peduncle. - Almost always in dry sand or sandy loam. ## Ecology A sandy-soil specialist of pine barrens, old fields and oak savanna. Blooms early, giving returning monarchs a host before common milkweed is ready. ## Growing Needs sand and sun; will not tolerate rich, moist beds. Handsome foliage all season. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:60445583-2 - GBIF: https://www.gbif.org/species/3170332 - iNaturalist: https://www.inaturalist.org/taxa/47910 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_amplexicaulis - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20amplexicaulis.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20amplexicaulis ## Photographs - Asclepias amplexicaulis leaves (Choess, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_amplexicaulis_leaves.JPG - Asclepias amplexicaulis Blue Ridge (Mason Brock (Masebrock), Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_amplexicaulis_Blue_Ridge.jpg - Asclepias amplexicaulis (14329407319) (Fritz Flohr Reynolds, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_amplexicaulis_(14329407319).jpg - Asclepias amplexicaulis (19733015086) ([https://www.flickr.com/photos/wackybadger/ Joshua Mayer (wackybadger), CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_amplexicaulis_(19733015086).jpg - Asclepias amplexicaulis (19752004992) (Joshua Mayer (wackybadger), CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_amplexicaulis_(19752004992).jpg - Asclepias amplexicaulis (cassi saari, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_amplexicaulis.jpg - Photographing Asclepias amplexicaulis at Nachusa Grasslands (cassi saari, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Photographing_Asclepias_amplexicaulis_at_Nachusa_Grasslands.jpg - Clasping MIlkweed (Asclepias amplexicaulis) - 19752025302 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Clasping_MIlkweed_(Asclepias_amplexicaulis)_-_19752025302.jpg ## How to cite Milkweed USA. (2026). Clasping Milkweed (Asclepias amplexicaulis). https://milkweedusa.com/species/clasping-milkweed/ --- # Common Milkweed (Asclepias syriaca) > The species that feeds the eastern monarch migration. Big paddle-shaped leaves, thick stems and heavy, drooping balls of dusty-pink flowers with a scent people describe as honey and vanilla. It is also an aggressive rhizomatous colonizer: magnificent in a meadow, a menace in a perennial border. Source: https://milkweedusa.com/species/common-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary The species that feeds the eastern monarch migration. Big paddle-shaped leaves, thick stems and heavy, drooping balls of dusty-pink flowers with a scent people describe as honey and vanilla. It is also an aggressive rhizomatous colonizer: magnificent in a meadow, a menace in a perennial border. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias syriaca L. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Common Milkweed, Silkweed, Virginia Silkweed | | Status | Native | | Height | 3 ft–6 ft | | Spread | 2 ft–10 ft | | Flower color | pink, mauve, white | | Bloom period | June to August | | Light | Full sun, Part shade | | Soil moisture | Dry, Average | | USDA zones | 3-9 | | Leaf arrangement | opposite | | Leaf shape | oblong | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 5 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 5 | | US states recorded | Alabama, Arkansas, Colorado, Connecticut, District of Columbia, Delaware, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Mississippi, Montana, North Carolina, North Dakota, Nebraska, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Virginia, Vermont, Wisconsin, West Virginia, Wyoming | ## Identification - Leaves are large, broad and oblong with a prominent pale midrib, felted underneath. - Flower clusters droop or nod rather than sitting flat on top of the stem. - Stems are stout, usually unbranched, and covered in fine downy hair. - Seed pods are fat, warty and covered in soft spines, unmistakable in the fall. ## Ecology No plant supports more eastern monarch caterpillars. Large, soft leaves let a single stem raise several larvae, and dense colonies give females an easy target from the air. The flowers are among the richest nectar sources in the North American flora, feeding honey bees, bumble bees, wasps, beetles and butterflies through midsummer. ## Growing Do not plant it in a small garden unless you intend to fight it. Rhizomes travel several feet a year and shoots pop up through lawns, paths and neighboring beds. In a meadow, hedgerow, ditch or dedicated monarch patch it is the best thing you can grow. Cut stems flush in the fall if you need to slow it, or grow it inside a sunk barrier. ## Cautions Toxic to livestock in quantity, though animals normally avoid it. The tough rhizomes make it a listed noxious weed in a few jurisdictions, so check locally before establishing it on agricultural land. ## Questions **Is common milkweed invasive?** It is native across eastern and central North America, so it is not invasive in the technical sense, but it is genuinely aggressive. Rhizomes spread several feet per year and it will colonize a bed. Site it where it can run. **How do I stop common milkweed spreading?** Plant it inside a buried root barrier at least 18 inches deep, or grow it in a bottomless container sunk in the ground. Cutting shoots at ground level as they appear will weaken a colony over several seasons. **Common milkweed or showy milkweed: which should I plant?** Longitude decides it. East of the Rockies, common milkweed. West of roughly the 100th meridian, showy milkweed (A. speciosa) is the regional equivalent and the better choice. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:319076-2 - GBIF: https://www.gbif.org/species/3170247 - iNaturalist: https://www.inaturalist.org/taxa/47911 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_syriaca - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20syriaca.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20syriaca ## Photographs - Asclepias syriaca - leaf (18716484236) (NY State IPM Program at Cornell University from New York, USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_-_leaf_(18716484236).jpg - Asclepias syriaca - inflorescence (18555007128) (NY State IPM Program at Cornell University from New York, USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_-_inflorescence_(18555007128).jpg - Asclepias syriaca - whole plant with seedpods (18555004978) (NY State IPM Program at Cornell University from New York, USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_-_whole_plant_with_seedpods_(18555004978).jpg - Asclepias syriaca - inflorescence (18555073280) (NY State IPM Program at Cornell University from New York, USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_-_inflorescence_(18555073280).jpg - 6 1 2014 milkweed (Asclepias syriaca) (Jrosenberry1, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:6_1_2014_milkweed_(Asclepias_syriaca).jpg - Asclepias syriaca (ваточник сирийский) возле урочища Яцево (Novoklimov, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_(%D0%B2%D0%B0%D1%82%D0%BE%D1%87%D0%BD%D0%B8%D0%BA_%D1%81%D0%B8%D1%80%D0%B8%D0%B9%D1%81%D0%BA%D0%B8%D0%B9)_%D0%B2%D0%BE%D0%B7%D0%BB%D0%B5_%D1%83%D1%80%D0%BE%D1%87%D0%B8%D1%89%D0%B0_%D0%AF%D1%86%D0%B5%D0%B2%D0%BE.jpg - Asclepias syriaca - stem (18745239231) (NY State IPM Program at Cornell University from New York, USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_syriaca_-_stem_(18745239231).jpg - Aphis nerii feeding on Asclepias syriaca in Almaty Botanical Garden (Ruslan Kastani, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Aphis_nerii_feeding_on_Asclepias_syriaca_in_Almaty_Botanical_Garden.jpg ## How to cite Milkweed USA. (2026). Common Milkweed (Asclepias syriaca). https://milkweedusa.com/species/common-milkweed/ --- # Curtiss’ Milkweed (Asclepias curtissii) > A Florida scrub endemic listed as endangered by the state, with wavy-edged pale leaves and greenish-white flowers, restricted to the ancient sand ridges of the peninsula. Source: https://milkweedusa.com/species/curtiss-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A Florida scrub endemic listed as endangered by the state, with wavy-edged pale leaves and greenish-white flowers, restricted to the ancient sand ridges of the peninsula. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias curtissii A. Gray | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Curtiss’ Milkweed, Curtiss’ Sandhill Milkweed | | Status | Native; rare or legally protected in part of its range | | Height | 1 ft–3 ft | | Spread | 10 in–1.7 ft | | Flower color | white, green | | Bloom period | April to September | | Light | Full sun, Part shade | | Soil moisture | Dry | | USDA zones | 8-10 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | None required | | Monarch value (0-5) | 3 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 2 | | US states recorded | Florida | ## Identification - Wavy-margined, pale gray-green leaves in widely spaced pairs. - Greenish-white flowers in open terminal clusters. - Only in Florida scrub and sandhill on relict dune ridges. ## Ecology Confined to Florida scrub, one of the most threatened habitats in North America, most of which has been converted to citrus and housing. ## Growing State-listed as endangered in Florida. Do not collect from the wild; buy only nursery-propagated stock. ## Cautions Endangered in Florida; collection from the wild is prohibited. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94214-1 - GBIF: https://www.gbif.org/species/3170342 - iNaturalist: https://www.inaturalist.org/taxa/146969 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_curtissii - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20curtissii.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20curtissii ## Photographs - Curtiss milkweed (Asclepias curtissii) (6023865184) (Bob Peterson from North Palm Beach, Florida, Planet Earth!, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Curtiss_milkweed_(Asclepias_curtissii)_(6023865184).jpg - Asclepias curtissii (Curtiss milkweed ) (5771618293) (Bob Peterson from North Palm Beach, Florida, Planet Earth!, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_curtissii_(Curtiss_milkweed_)_(5771618293).jpg - Asclepias curtissii (6162805747) (scott.zona from Miami, Florida, USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_curtissii_(6162805747).jpg - Curtiss’ Milkweed photographed in United States (Scott Allen Davis, CC BY 4.0): https://www.inaturalist.org/observations/21429606 - Curtiss’ Milkweed photographed in Florida, US (Jay Horn, CC BY 4.0): https://www.inaturalist.org/observations/25915381 - Curtiss’ Milkweed photographed in Florida, US (Alex Abair, CC BY 4.0): https://www.inaturalist.org/observations/32718743 - Curtiss’ Milkweed photographed in Florida, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/3871734 - Curtiss’ Milkweed photographed in Florida, US (Scott Ward, CC BY 4.0): https://www.inaturalist.org/observations/57734329 ## How to cite Milkweed USA. (2026). Curtiss’ Milkweed (Asclepias curtissii). https://milkweedusa.com/species/curtiss-milkweed/ --- # Desert Milkweed (Asclepias erosa) > A big, pale, upright milkweed of the Mojave and Sonoran deserts, with chalky white stems, thick cream-edged leaves and heavy clusters of yellowish-white flowers that persist through the hottest months. Source: https://milkweedusa.com/species/desert-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A big, pale, upright milkweed of the Mojave and Sonoran deserts, with chalky white stems, thick cream-edged leaves and heavy clusters of yellowish-white flowers that persist through the hottest months. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias erosa Torr. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Desert Milkweed, Erose Milkweed | | Status | Native | | Height | 2 ft–5 ft | | Spread | 1.5 ft–3 ft | | Flower color | cream, yellow | | Bloom period | April to September | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 8-11 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, California, Nevada, Utah | ## Identification - Tall stiff stems that look bleached white or very pale green. - Thick leaves with pale, often crisped or eroded-looking margins. - Large clusters of cream-yellow flowers, blooming in true desert heat. ## Ecology One of very few milkweeds available to monarchs and queens in the low desert during summer, often along washes and roadsides. ## Growing Excellent in a Southwest desert garden: architectural, heat-proof and long-blooming. Needs full sun and fast drainage. ## Cautions Standard milkweed cautions. ## Questions **What milkweed grows in Arizona?** Desert milkweed (A. erosa) and pineneedle milkweed (A. linaria) for the low desert, antelope horns and rush milkweed in the transition zones, and showy milkweed at higher elevations along streams. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94260-1 - GBIF: https://www.gbif.org/species/3170333 - iNaturalist: https://www.inaturalist.org/taxa/57907 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_erosa - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20erosa.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20erosa ## Photographs - Asclepias erosa stem (Mike, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_erosa_stem.jpg - Asclepias erosa 1 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_erosa_1.jpg - Asclepias erosa 2 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_erosa_2.jpg - Asclepias erosa 3 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_erosa_3.jpg - Asclepias erosa 4 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_erosa_4.jpg - Asclepias erosa 5 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_erosa_5.jpg - Asclepias erosa 6 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_erosa_6.jpg - Asclepias erosa 7 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_erosa_7.jpg ## How to cite Milkweed USA. (2026). Desert Milkweed (Asclepias erosa). https://milkweedusa.com/species/desert-milkweed/ --- # Dwarf Milkweed (Asclepias involucrata) > A tiny, ground-hugging desert milkweed with wavy narrow leaves and pale green flowers held almost at soil level, found on sand and gravel across the Southwest. Source: https://milkweedusa.com/species/dwarf-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A tiny, ground-hugging desert milkweed with wavy narrow leaves and pale green flowers held almost at soil level, found on sand and gravel across the Southwest. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias involucrata Engelm. ex Torr. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Dwarf Milkweed, Involucrate Milkweed | | Status | Native | | Height | 4 in–10 in | | Spread | 10 in–1.7 ft | | Flower color | green, cream | | Bloom period | April to June | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 5-9 | | Leaf arrangement | opposite | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 60 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Arizona, Colorado, Kansas, New Mexico, Nevada, Oklahoma, Texas, Utah | ## Identification - Under a foot tall, with stems spreading flat from a central crown. - Leaf margins conspicuously wavy or crisped. - Flowers greenish-cream in clusters nestled among the leaves. ## Ecology A minor but genuine early-season host in desert grassland. ## Growing Effectively never cultivated. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94357-1 - GBIF: https://www.gbif.org/species/3170243 - iNaturalist: https://www.inaturalist.org/taxa/158743 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_involucrata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20involucrata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20involucrata ## Photographs - Asclepias involucrata - Craig Martin 01 (Craig Martin https://www.inaturalist.org/people/craigmartin, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_involucrata_-_Craig_Martin_01.jpg - WS-outdoor-southeast-gallery-15 (32778828473) (USEPA Environmental-Protection-Agency, Public domain): https://commons.wikimedia.org/wiki/File:WS-outdoor-southeast-gallery-15_(32778828473).jpg - Near Cañada Montosa - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Near_Ca%C3%B1ada_Montosa_-_Flickr_-_aspidoscelis.jpg - Near Cerro de Corazon - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Near_Cerro_de_Corazon_-_Flickr_-_aspidoscelis.jpg - Dwarf Milkweed photographed in Rio Arriba County, NM, USA (Public domain (CC0), CC0): https://www.inaturalist.org/observations/24340350 - Dwarf Milkweed photographed in Grant County, NM, USA (Andrew Tree, CC BY 4.0): https://www.inaturalist.org/observations/291243715 - Dwarf Milkweed photographed in Santa Fe County, US-NM, US (Anders Hastings, CC BY 4.0): https://www.inaturalist.org/observations/166490260 - Dwarf Milkweed photographed in Torrance County, NM, USA (Dominic Gentilcore, CC BY 4.0): https://www.inaturalist.org/observations/96389901 ## How to cite Milkweed USA. (2026). Dwarf Milkweed (Asclepias involucrata). https://milkweedusa.com/species/dwarf-milkweed/ --- # Eastwood’s Milkweed (Asclepias eastwoodiana) > A Nevada endemic of barren volcanic gravel and clay flats in the central Great Basin, forming low gray-green tufts with dusky maroon and cream flowers. Known from a small number of populations and tracked as a sensitive species. Source: https://milkweedusa.com/species/eastwoods-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A Nevada endemic of barren volcanic gravel and clay flats in the central Great Basin, forming low gray-green tufts with dusky maroon and cream flowers. Known from a small number of populations and tracked as a sensitive species. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias eastwoodiana Barneby | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Eastwood’s Milkweed, Great Basin Milkweed | | Status | Native; rare or legally protected in part of its range | | Height | 6 in–1.2 ft | | Spread | 10 in–1.7 ft | | Flower color | maroon, cream | | Bloom period | May to June | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 5-8 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 60 days cold-moist | | Monarch value (0-5) | 1 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Nevada | ## Identification - Low, tufted habit on bare volcanic or ash-derived soils. - Greyish, softly hairy, broadly oval leaves. - Small flowers with maroon corolla lobes and pale cream hoods. ## Ecology A narrow endemic of a habitat type increasingly targeted for mineral exploration. Its pollinators and larval use are poorly documented. ## Growing Not in cultivation, and should not be collected. ## Cautions A restricted Nevada endemic. Record and report sightings rather than collecting. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21182-2 - GBIF: https://www.gbif.org/species/3578016 - iNaturalist: https://www.inaturalist.org/taxa/541501 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_eastwoodiana - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20eastwoodiana.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20eastwoodiana ## Photographs - Asclepias eastwoodiana (Matt Berger (sheriff_woody_pct on inaturalist), CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_eastwoodiana.jpg - Eastwood’s Milkweed photographed in Dave Deacon Camp Rd, Tonopah, NV, US (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/165012799 - Eastwood’s Milkweed photographed in Nevada, US (sdash, CC BY 4.0): https://www.inaturalist.org/observations/285914781 - Eastwood’s Milkweed photographed in Dave Deacon Camp Rd, Tonopah, NV, US (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/165012799 - Eastwood’s Milkweed photographed in Dave Deacon Camp Rd, Tonopah, NV, US (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/165012799 - Eastwood’s Milkweed photographed in Dave Deacon Camp Rd, Tonopah, NV, US (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/165012799 - Eastwood’s Milkweed photographed in Dave Deacon Camp Rd, Tonopah, NV, US (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/165012799 - Eastwood’s Milkweed photographed in Dave Deacon Camp Rd, Tonopah, NV, US (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/165012799 ## How to cite Milkweed USA. (2026). Eastwood’s Milkweed (Asclepias eastwoodiana). https://milkweedusa.com/species/eastwoods-milkweed/ --- # Emory’s Milkweed (Asclepias emoryi) > A low, wiry Chihuahuan Desert milkweed of gypsum and caliche flats in west Texas and southern New Mexico, flowering greenish-cream after any decent rain. Source: https://milkweedusa.com/species/emorys-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A low, wiry Chihuahuan Desert milkweed of gypsum and caliche flats in west Texas and southern New Mexico, flowering greenish-cream after any decent rain. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias emoryi (Greene) Vail | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Emory’s Milkweed | | Status | Native | | Height | 4 in–1.2 ft | | Spread | 10 in–1.8 ft | | Flower color | green, cream | | Bloom period | April to September | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 7-10 | | Leaf arrangement | opposite | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | New Mexico, Texas | ## Identification - Low sprawling stems with narrow, often folded opposite leaves. - Small greenish flowers in compact clusters. - Gypsum, caliche and other harsh calcareous desert soils. ## Ecology Opportunistic flowering after rain makes it available to monarchs and queens at unpredictable times through the season. ## Growing Not in cultivation. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21184-2 - GBIF: https://www.gbif.org/species/8076255 - iNaturalist: https://www.inaturalist.org/taxa/158737 - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20emoryi.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20emoryi ## Photographs - Near Arrastra Gulch - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Near_Arrastra_Gulch_-_Flickr_-_aspidoscelis.jpg - Emory’s Milkweed photographed in 78588, San Isidro, TX, US (Cat, CC BY 4.0): https://www.inaturalist.org/observations/18509370 - Emory’s Milkweed photographed in Texas, US (Tamara T, CC BY 4.0): https://www.inaturalist.org/observations/5374688 - Emory’s Milkweed photographed in Pleasanton, TX 78064, USA (Cleveland Powell, CC BY 4.0): https://www.inaturalist.org/observations/354004708 - Emory’s Milkweed photographed in County Road 369, Sandia, TX, US (Chet Burrier, CC BY 4.0): https://www.inaturalist.org/observations/365185098 - Emory’s Milkweed photographed in Texas, US (Michelle W. （鍾偉瑋）, CC BY 4.0): https://www.inaturalist.org/observations/155196303 - Emory’s Milkweed photographed in Rocksprings, TX 78880, USA (Jo Roberts, CC BY 4.0): https://www.inaturalist.org/observations/80814342 - Emory’s Milkweed photographed in FM-755, Rio Grande City, TX, US (Jason K., CC BY 4.0): https://www.inaturalist.org/observations/288171889 ## How to cite Milkweed USA. (2026). Emory’s Milkweed (Asclepias emoryi). https://milkweedusa.com/species/emorys-milkweed/ --- # Engelmann’s Milkweed (Asclepias engelmanniana) > A tall, sparse, almost skeletal prairie milkweed with long drooping linear leaves and small greenish-yellow flowers. It looks fragile and is anything but, with a taproot that goes deep into sandy plains soil. Source: https://milkweedusa.com/species/engelmanns-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A tall, sparse, almost skeletal prairie milkweed with long drooping linear leaves and small greenish-yellow flowers. It looks fragile and is anything but, with a taproot that goes deep into sandy plains soil. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias engelmanniana Woodson | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Engelmann’s Milkweed | | Status | Native | | Height | 2 ft–5 ft | | Spread | 1 ft–2 ft | | Flower color | green, yellow | | Bloom period | June to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 4-8 | | Leaf arrangement | alternate | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 3 | | US states recorded | Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, Wyoming | ## Identification - Very long, narrow, drooping alternate leaves on a tall slender stem. - Small greenish-yellow flowers in loose clusters from the upper leaf axils. - Distinctly gaunt outline compared with other plains milkweeds. ## Ecology A sandhills and shortgrass species used by monarchs during the fall migration through the central flyway. ## Growing Rarely cultivated. Needs deep sand and full exposure. ## Cautions Standard narrow-leaf milkweed toxicity. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:290400-2 - GBIF: https://www.gbif.org/species/3170267 - iNaturalist: https://www.inaturalist.org/taxa/158738 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_engelmanniana - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20engelmanniana.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20engelmanniana ## Photographs - Asclepias engelmanniana - scevola augustin 02 (scevola_augustin, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_engelmanniana_-_scevola_augustin_02.jpg - Asclepias engelmanniana - scevola augustin 01 (scevola_augustin, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_engelmanniana_-_scevola_augustin_01.jpg - Asclepias engelmanniana - scevola augustin 03 (scevola_augustin, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_engelmanniana_-_scevola_augustin_03.jpg - Asclepias engelmanniana - scevola augustin 04 (scevola_augustin, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_engelmanniana_-_scevola_augustin_04.jpg - Asclepias engelmanniana - Scott Allen Davis 01 (Scott Allen Davis, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_engelmanniana_-_Scott_Allen_Davis_01.jpg - Engelmann’s Milkweed photographed in Texas, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/220272868 - Engelmann’s Milkweed photographed in Longmont, CO, US (Jess Mullins, CC BY 4.0): https://www.inaturalist.org/observations/52210011 - Engelmann’s Milkweed photographed in US-180, Lamesa, TX, US (samlutfy, CC BY 4.0): https://www.inaturalist.org/observations/58794482 ## How to cite Milkweed USA. (2026). Engelmann’s Milkweed (Asclepias engelmanniana). https://milkweedusa.com/species/engelmanns-milkweed/ --- # Feay’s Milkweed (Asclepias feayi) > A Florida endemic of pine flatwoods and sandhill with hair-fine leaves and delicate white flowers flushed pink, so slender that the plant almost disappears into the wiregrass. Source: https://milkweedusa.com/species/feays-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A Florida endemic of pine flatwoods and sandhill with hair-fine leaves and delicate white flowers flushed pink, so slender that the plant almost disappears into the wiregrass. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias feayi Chapm. ex A. Gray | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Feay’s Milkweed, Florida Milkweed | | Status | Native | | Height | 8 in–2 ft | | Spread | 8 in–1.3 ft | | Flower color | white, pink | | Bloom period | April to September | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 8-10 | | Leaf arrangement | opposite | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | None required | | Monarch value (0-5) | 3 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 2 | | US states recorded | Florida | ## Identification - Extremely fine, thread-like opposite leaves. - Small white flowers with a pink or lavender tinge, in airy clusters. - Florida pine flatwoods, sandhill and dry prairie, statewide except the far west. ## Ecology A fire-maintained flatwoods species and a genuine Florida endemic, used by monarchs and queens through the long southern season. ## Growing Occasionally offered by Florida native nurseries. Needs sand, sun and no irrigation. Fresh seed germinates without chilling. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94274-1 - GBIF: https://www.gbif.org/species/3170275 - iNaturalist: https://www.inaturalist.org/taxa/143039 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_feayi - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20feayi.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20feayi ## Photographs - Asclepias feayi 1a (jimduggan24, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_feayi_1a.jpg - Asclepias feayi - Boyd Hill, St Petersburg, FL - August 2025 (Dsandii, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_feayi_-_Boyd_Hill,_St_Petersburg,_FL_-_August_2025.jpg - Feay’s Milkweed photographed in Alva, FL 33920, USA (Jay Horn, CC BY 4.0): https://www.inaturalist.org/observations/45307435 - Feay’s Milkweed photographed in Sarasota, FL 34240, USA (Scott Allen Davis, CC BY 4.0): https://www.inaturalist.org/observations/196735863 - Feay’s Milkweed photographed in Unnamed Road, St Cloud, FL 34771, USA (Valerie Anderson, CC BY 4.0): https://www.inaturalist.org/observations/12194297 - Feay’s Milkweed photographed in Florida, US (Brandon Corder, CC BY 4.0): https://www.inaturalist.org/observations/118830752 - Feay’s Milkweed photographed in North South Trail North Loop, Orlando, FL, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/309281554 - Feay’s Milkweed photographed in Yeehaw, FL 34972, USA (Laura Gaudette, CC BY 4.0): https://www.inaturalist.org/observations/114989776 ## How to cite Milkweed USA. (2026). Feay’s Milkweed (Asclepias feayi). https://milkweedusa.com/species/feays-milkweed/ --- # Fewflower Milkweed (Asclepias lanceolata) > A tall, sparse, brilliant orange-red milkweed of coastal marsh and wet savanna. Imagine butterfly weed stretched to five feet, standing in a brackish ditch with only a handful of flowers per head. Source: https://milkweedusa.com/species/fewflower-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A tall, sparse, brilliant orange-red milkweed of coastal marsh and wet savanna. Imagine butterfly weed stretched to five feet, standing in a brackish ditch with only a handful of flowers per head. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias lanceolata Walter | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Fewflower Milkweed, Cedar Hill Milkweed, Purple Silkweed | | Status | Native | | Height | 2 ft–5 ft | | Spread | 10 in–1.5 ft | | Flower color | orange, red | | Bloom period | May to August | | Light | Full sun | | Soil moisture | Wet | | USDA zones | 6-10 | | Leaf arrangement | opposite | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Fibrous, clump-forming and easy to move | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 4 | | US states recorded | Alabama, Delaware, Florida, Georgia, Louisiana, Maryland, Mississippi, North Carolina, New Jersey, South Carolina, Texas, Virginia | ## Identification - Tall unbranched stem with very few, very narrow leaf pairs. - Flowers vivid orange-red, in small clusters of a dozen or fewer. - Coastal wetlands, brackish marsh edges and wet pine savanna. ## Ecology A striking nectar plant in coastal wetlands and a modest monarch host along the Atlantic and Gulf coasts. ## Growing Needs constantly wet, acidic soil and full sun, so treat it as a bog garden plant. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30049929-2 - GBIF: https://www.gbif.org/species/3170251 - iNaturalist: https://www.inaturalist.org/taxa/158744 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_lanceolata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20lanceolata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20lanceolata ## Photographs - Asclepias lanceolata plant (Happypixie, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_lanceolata_plant.jpg - Asclepias lanceolata (9099845297) (Everglades NPS from Homestead, Florida, United States, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_lanceolata_(9099845297).jpg - Asclepias lanceolata (9099844995) (Everglades NPS from Homestead, Florida, United States, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_lanceolata_(9099844995).jpg - Asclepias lanceolata (WendyAvilesR, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_lanceolata.jpg - Asclepias lanceolata 386072019 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_lanceolata_386072019.jpg - Asclepias lanceolata 386071992 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_lanceolata_386071992.jpg - Asclepias lanceolata 386072038 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_lanceolata_386072038.jpg - Asclepias lanceolata 386072022 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_lanceolata_386072022.jpg ## How to cite Milkweed USA. (2026). Fewflower Milkweed (Asclepias lanceolata). https://milkweedusa.com/species/fewflower-milkweed/ --- # Fourleaf Milkweed (Asclepias quadrifolia) > A delicate spring milkweed of dry oak woodland: a slim stem carrying one whorl of four broad leaves at mid-height and a small airy cluster of pale pink flowers. The earliest milkweed to bloom across much of the East. Source: https://milkweedusa.com/species/fourleaf-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A delicate spring milkweed of dry oak woodland: a slim stem carrying one whorl of four broad leaves at mid-height and a small airy cluster of pale pink flowers. The earliest milkweed to bloom across much of the East. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias quadrifolia Jacq. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Fourleaf Milkweed, Whorled Woodland Milkweed | | Status | Native | | Height | 1 ft–2 ft | | Spread | 9 in–1.3 ft | | Flower color | pink, white | | Bloom period | May to June | | Light | Part shade, Shade | | Soil moisture | Dry, Average | | USDA zones | 4-8 | | Leaf arrangement | whorled | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 3 | | US states recorded | Alabama, Arkansas, Connecticut, District of Columbia, Delaware, Georgia, Iowa, Illinois, Indiana, Kentucky, Massachusetts, Maryland, Michigan, Missouri, Mississippi, North Carolina, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, Vermont, West Virginia | ## Identification - A single whorl of four leaves partway up the stem, with opposite pairs above and below it. - Small, pale pink to nearly white flowers in a loose cluster. - Under two feet tall, growing in dry woodland shade. - Flowers in May, weeks before other eastern milkweeds. ## Ecology One of very few milkweeds available to the earliest arriving monarchs in the Appalachians and Ozarks, and useful to spring woodland bees. ## Growing Charming in a woodland garden with dry, well-drained, leafy soil. Goes dormant early. Never dig from the wild; buy nursery-propagated stock. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94581-1 - GBIF: https://www.gbif.org/species/3170257 - iNaturalist: https://www.inaturalist.org/taxa/129548 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_quadrifolia - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20quadrifolia.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20quadrifolia ## Photographs - Asclepias quadrifolia 001 (Halpaugh, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_quadrifolia_001.jpg - Asclepias quadrifolia (Eric Hunt, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_quadrifolia.jpg - Asclepias quadrifolia 511684130 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_quadrifolia_511684130.jpg - Asclepias quadrifolia 511684135 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_quadrifolia_511684135.jpg - Asclepias quadrifolia 511684117 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_quadrifolia_511684117.jpg - Asclepias quadrifolia 511684147 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_quadrifolia_511684147.jpg - Asclepias quadrifolia 652500784 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_quadrifolia_652500784.jpg - Asclepias quadrifolia 652500764 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_quadrifolia_652500764.jpg ## How to cite Milkweed USA. (2026). Fourleaf Milkweed (Asclepias quadrifolia). https://milkweedusa.com/species/fourleaf-milkweed/ --- # Giant Milkweed (Calotropis procera) > A large shrub or small tree from Africa and Asia, naturalised in the warmest parts of the United States. Its huge blue-gray leaves and waxy purple-tipped white flowers make it a striking plant, and monarchs and queens use it as a host, but it is invasive on disturbed dry ground. Source: https://milkweedusa.com/species/giant-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A large shrub or small tree from Africa and Asia, naturalised in the warmest parts of the United States. Its huge blue-gray leaves and waxy purple-tipped white flowers make it a striking plant, and monarchs and queens use it as a host, but it is invasive on disturbed dry ground. ## Key facts | Field | Value | | --- | --- | | Scientific name | Calotropis procera (Aiton) W.T. Aiton | | Genus | Calotropis | | Family | Apocynaceae | | Common names | Giant Milkweed, Rooster Tree, Sodom Apple, Calotrope | | Status | Not native to the United States | | Height | 6 ft–12 ft | | Spread | 4 ft–8 ft | | Flower color | white, purple | | Bloom period | nearly year-round in frost-free areas | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 9-11 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | None required | | Monarch value (0-5) | 3 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, California, Florida, Hawaii, Texas | ## Identification - Shrub or small tree to twelve feet, far larger than any native milkweed. - Very large, thick, blue-gray leaves clasping stout woody stems. - Waxy white flowers with five purple-tipped lobes, in dense clusters. - Sap is copious, thick and strongly irritant. ## Ecology Used by monarch and queen larvae in Florida, Hawaii and south Texas. It colonizes overgrazed and disturbed dry ground aggressively and is treated as invasive in parts of its introduced range. ## Growing Not recommended for planting in the United States. Where it is already present, monarchs will use it, but it displaces native vegetation and its sap is a serious hazard. ## Cautions Non-native and invasive on dry disturbed ground. The latex is a severe skin and eye irritant, considerably more so than native milkweeds, and the whole plant is toxic. Wear eye protection if cutting it. ## Questions **Can monarchs eat giant milkweed?** Yes, monarch and queen larvae develop on Calotropis procera, and it is a common host in Florida, Hawaii and south Texas. It is not native to the United States, is invasive on disturbed dry land, and its sap is a much stronger irritant than any native milkweed. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:1004515-2 - GBIF: https://www.gbif.org/species/5414566 - iNaturalist: https://www.inaturalist.org/taxa/120917 - Wikipedia: https://en.wikipedia.org/wiki/Calotropis_procera - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Calotropis%20procera ## Photographs - Calotropis procera flower (Habibtadese, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Calotropis_procera_flower.jpg - Calotropis procera plant (Knowledge and philosophy, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Calotropis_procera_plant.jpg - Flower of Giant Milkweed (Calotropis procera) from Rajasthan, India (Kingshuk Mondal, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Flower_of_Giant_Milkweed_(Calotropis_procera)_from_Rajasthan,_India.jpg - Giant Milkweed photographed in Rishon LeTsiyon, Israel (hadanie7, CC BY 4.0): https://www.inaturalist.org/observations/140245140 - Giant Milkweed photographed in Zacapa Department, Guatemala (Juanito Escamilla, CC BY 4.0): https://www.inaturalist.org/observations/85260038 - Giant Milkweed photographed in Teculután, Guatemala (Saban-Sequén, E.A., CC BY 4.0): https://www.inaturalist.org/observations/78107575 - Giant Milkweed photographed in Nazwah, Dubai, Dubai, AE (pavlaki1968, CC BY 4.0): https://www.inaturalist.org/observations/108798077 - Giant Milkweed photographed in Kondapalli, Andhra Pradesh 521228, India (Raja bandi, CC BY 4.0): https://www.inaturalist.org/observations/72226559 ## How to cite Milkweed USA. (2026). Giant Milkweed (Calotropis procera). https://milkweedusa.com/species/giant-milkweed/ --- # Green Antelopehorn (Asclepias viridis) > The workhorse of the south-central states: sprawling stems, broad wavy leaves and big open clusters of pale green flowers with purple-tinged centers, blooming early across pasture, roadside and prairie from Texas to Tennessee. Source: https://milkweedusa.com/species/green-antelopehorn/ Licence: CC BY 4.0 (Milkweed USA) ## Summary The workhorse of the south-central states: sprawling stems, broad wavy leaves and big open clusters of pale green flowers with purple-tinged centers, blooming early across pasture, roadside and prairie from Texas to Tennessee. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias viridis Walter | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Green Antelopehorn, Green Milkweed, Spider Milkweed | | Status | Native | | Height | 1 ft–2.5 ft | | Spread | 1.5 ft–3 ft | | Flower color | green, purple | | Bloom period | April to July | | Light | Full sun | | Soil moisture | Dry, Average | | USDA zones | 5-9 | | Leaf arrangement | alternate | | Leaf shape | oblong | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 5 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Alabama, Arkansas, Colorado, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Missouri, Mississippi, Nebraska, New Mexico, Oklahoma, South Carolina, Tennessee, Texas | ## Identification - Flowers pale green with a purplish crown, in large loose clusters at the stem tips. - Leaves broad, alternate and often with wavy edges. - Stems lean and sprawl outward from the base. - Very common on unimproved pasture and roadsides in Texas and Oklahoma. ## Ecology Along with antelope horns, this is the plant that receives the first northbound monarchs in the south-central flyway each spring, which arguably makes it the highest-leverage milkweed on the continent. ## Growing Tough, drought-proof and long-lived on lean soils. Direct-sow; the taproot dislikes transplanting. Goes dormant in high summer heat. ## Cautions Toxic to livestock in quantity, though rarely eaten by choice. ## Questions **What is the best milkweed to plant in Texas?** Green antelopehorn (A. viridis) and antelope horns (A. asperula) are the two native species that matter most for spring monarchs, with zizotes milkweed and butterfly weed also excellent. Avoid tropical milkweed, because Texas winters are mild enough for it to cause year-round breeding. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94737-1 - GBIF: https://www.gbif.org/species/3170294 - iNaturalist: https://www.inaturalist.org/taxa/60946 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_viridis - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20viridis.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20viridis ## Photographs - Asclepias viridis (Marion Doss, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_viridis.jpg - Asclepias viridis 1 (mmarchin, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_viridis_1.jpg - Asclepias viridis (9123680137) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_viridis_(9123680137).jpg - Asclepias viridis (9123678969) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_viridis_(9123678969).jpg - Asclepias viridis Arkansas (Eric Hunt, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_viridis_Arkansas.jpg - Asclepias viridis - 49926816687 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_viridis_-_49926816687.jpg - Asclepias viridis - 49839858577 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_viridis_-_49839858577.jpg - Asclepias viridis (2020) (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_viridis_(2020).jpg ## How to cite Milkweed USA. (2026). Green Antelopehorn (Asclepias viridis). https://milkweedusa.com/species/green-antelopehorn/ --- # Green Comet Milkweed (Asclepias viridiflora) > A subtle, wide-ranging prairie milkweed with tight ball-shaped clusters of purely green flowers pressed against the stem. Enormously variable in leaf shape across its range, from broad and wavy to narrow and folded, which makes it one of the most confusing milkweeds to key out. Source: https://milkweedusa.com/species/green-comet-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A subtle, wide-ranging prairie milkweed with tight ball-shaped clusters of purely green flowers pressed against the stem. Enormously variable in leaf shape across its range, from broad and wavy to narrow and folded, which makes it one of the most confusing milkweeds to key out. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias viridiflora Raf. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Green Comet Milkweed, Green Milkweed, Short Green Milkweed | | Status | Native | | Height | 1 ft–3 ft | | Spread | 1 ft–1.7 ft | | Flower color | green | | Bloom period | May to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 3-9 | | Leaf arrangement | opposite | | Leaf shape | elliptic | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Alabama, Arkansas, Arizona, Colorado, Connecticut, Delaware, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Missouri, Mississippi, Montana, North Carolina, North Dakota, Nebraska, New Jersey, New Mexico, New York, Ohio, Oklahoma, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Wisconsin, West Virginia, Wyoming | ## Identification - Flowers entirely green with no purple or white, in dense sessile or short-stalked clusters. - Leaves thick and often with wavy margins; shape varies wildly between populations. - Stems usually single, sometimes leaning; the whole plant is understated and easy to walk past. ## Ecology Found on dry prairie, glades, sand and thin rocky soil across most of the continent. Used by monarchs, though its scattered distribution means it is rarely a major host. Wasps and small bees dominate the flowers. ## Growing A collector’s plant rather than a landscape one. Needs perfect drainage and lean soil, and the taproot makes container-raised plants tricky to establish. Slow but very long-lived. ## Cautions Standard milkweed cautions apply; not a significant livestock risk given its scattered occurrence. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:1167930-2 - GBIF: https://www.gbif.org/species/3170313 - iNaturalist: https://www.inaturalist.org/taxa/158763 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_viridiflora - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20viridiflora.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20viridiflora ## Photographs - Green-flowered Milkweed (Asclepias viridiflora) (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Green-flowered_Milkweed_(Asclepias_viridiflora).jpg - Green-flowered Milkweed (Asclepias viridiflora) - 14785916461 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Green-flowered_Milkweed_(Asclepias_viridiflora)_-_14785916461.jpg - Green-flowered Milkweed (Asclepias viridiflora) - 14788711822 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Green-flowered_Milkweed_(Asclepias_viridiflora)_-_14788711822.jpg - Green-flowered Milkweed (Asclepias viridiflora) - 14808904633 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Green-flowered_Milkweed_(Asclepias_viridiflora)_-_14808904633.jpg - Green-flowered Milkweed (Asclepias viridiflora) - 14602357590 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Green-flowered_Milkweed_(Asclepias_viridiflora)_-_14602357590.jpg - Green-flowered Milkweed (Asclepias viridiflora) - 14602399299 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Green-flowered_Milkweed_(Asclepias_viridiflora)_-_14602399299.jpg - Green-flowered Milkweed (Asclepias viridiflora) - 14602400849 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Green-flowered_Milkweed_(Asclepias_viridiflora)_-_14602400849.jpg - Green-flowered Milkweed (Asclepias viridiflora) - 19414954118 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Green-flowered_Milkweed_(Asclepias_viridiflora)_-_19414954118.jpg ## How to cite Milkweed USA. (2026). Green Comet Milkweed (Asclepias viridiflora). https://milkweedusa.com/species/green-comet-milkweed/ --- # Hall’s Milkweed (Asclepias hallii) > A handsome southern Rocky Mountain endemic with soft pink-mauve flower clusters and grayish lance-shaped leaves, growing on dry mesas, sandy foothills and piñon-juniper edges from Colorado to Nevada. Source: https://milkweedusa.com/species/halls-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A handsome southern Rocky Mountain endemic with soft pink-mauve flower clusters and grayish lance-shaped leaves, growing on dry mesas, sandy foothills and piñon-juniper edges from Colorado to Nevada. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias hallii A. Gray | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Hall’s Milkweed, Purple Silkweed | | Status | Native | | Height | 1.5 ft–3 ft | | Spread | 1.5 ft–3 ft | | Flower color | pink, mauve | | Bloom period | June to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 4-8 | | Leaf arrangement | opposite | | Leaf shape | lanceolate | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 4 | | US states recorded | Arizona, Colorado, New Mexico, Nevada, Utah, Wyoming | ## Identification - Resembles a slimmer, drier-country showy milkweed with narrower leaves and smaller flowers. - Flower clusters are terminal and upright, pale pink to dull rose. - Stems often several from a spreading rootstock, sometimes forming loose colonies. ## Ecology A significant monarch host on Colorado’s Western Slope and across the Colorado Plateau, where large-leaved milkweeds are scarce. ## Growing Excellent for xeric gardens in the Interior West, though seed is hard to source. Needs sharp drainage and full sun. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94337-1 - GBIF: https://www.gbif.org/species/3170237 - iNaturalist: https://www.inaturalist.org/taxa/158741 - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20hallii.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20hallii ## Photographs - Fort Bayard - Flickr - aspidoscelis (20) (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Fort_Bayard_-_Flickr_-_aspidoscelis_(20).jpg - Near Border Hill - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Near_Border_Hill_-_Flickr_-_aspidoscelis.jpg - Fort Stanton Mesa - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Fort_Stanton_Mesa_-_Flickr_-_aspidoscelis.jpg - Near Ft. Stanton - Flickr - aspidoscelis (4) (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Near_Ft._Stanton_-_Flickr_-_aspidoscelis_(4).jpg - Hall’s Milkweed photographed in Colorado, US (Ryan Sorrells, CC BY 4.0): https://www.inaturalist.org/observations/229442566 - Hall’s Milkweed photographed in Chaffee County, US-CO, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/30958195 - Hall’s Milkweed photographed in Fremont County, CO, USA (Anders Hastings, CC BY 4.0): https://www.inaturalist.org/observations/294085062 - Hall’s Milkweed photographed in Arkansas River Trail, Buena Vista, CO, US (Brad Grimm, CC BY 4.0): https://www.inaturalist.org/observations/293208490 ## How to cite Milkweed USA. (2026). Hall’s Milkweed (Asclepias hallii). https://milkweedusa.com/species/halls-milkweed/ --- # Heartleaf Milkweed (Asclepias cordifolia) > Arguably the handsomest milkweed in the West: smooth, waxy, blue-gray heart-shaped leaves clasping arching purple stems, hung with clusters of dark wine-red flowers. A Sierra Nevada and Cascade foothill specialty. Source: https://milkweedusa.com/species/heartleaf-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary Arguably the handsomest milkweed in the West: smooth, waxy, blue-gray heart-shaped leaves clasping arching purple stems, hung with clusters of dark wine-red flowers. A Sierra Nevada and Cascade foothill specialty. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias cordifolia (Benth.) Jeps. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Heartleaf Milkweed, Purple Milkweed | | Status | Native | | Height | 1 ft–3 ft | | Spread | 1.5 ft–2.5 ft | | Flower color | maroon, purple | | Bloom period | May to July | | Light | Full sun, Part shade | | Soil moisture | Dry | | USDA zones | 6-9 | | Leaf arrangement | opposite | | Leaf shape | cordate | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 5 | | Nectar value (0-5) | 3 | | US states recorded | California, Nevada, Oregon | ## Identification - Leaves distinctly heart-shaped, clasping the stem, smooth and blue-glaucous. - Stems often flushed purple and arching. - Flowers deep red-purple with paler hoods, in loose nodding clusters. - Rocky slopes and open conifer forest, 1,000 to 6,500 feet. ## Ecology A key early host for western monarchs moving into the Sierra foothills, and one of the earliest western milkweeds to leaf out. ## Growing Outstanding foliage plant for a dry mountain garden. Needs excellent drainage, some afternoon shade at low elevation, and no summer water. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21169-2 - GBIF: https://www.gbif.org/species/3170280 - iNaturalist: https://www.inaturalist.org/taxa/62248 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_cordifolia - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20cordifolia.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20cordifolia ## Photographs - Asclepias cordifolia (First Light (talk), CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_cordifolia.JPG - Asclepias cordifolia (9105035433) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_cordifolia_(9105035433).jpg - Heartleaf Milkweed photographed in Plumas County, CA, USA (Steve Matson, CC BY 4.0): https://www.inaturalist.org/observations/56348191 - Heartleaf Milkweed photographed in Tuolumne County, CA, USA (Michael Warner, CC BY 4.0): https://www.inaturalist.org/observations/170586529 - Heartleaf Milkweed photographed in El Dorado County, US-CA, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/82018421 - Heartleaf Milkweed photographed in Alpine County, CA, USA (Tim Messick, CC BY 4.0): https://www.inaturalist.org/observations/220301183 - Heartleaf Milkweed photographed in Briones, CA 94553, USA (Ken-ichi Ueda, CC BY 4.0): https://www.inaturalist.org/observations/283830447 - Heartleaf Milkweed photographed in Washoe County, NV, USA (Spencer Hurt, CC BY 4.0): https://www.inaturalist.org/observations/363969442 ## How to cite Milkweed USA. (2026). Heartleaf Milkweed (Asclepias cordifolia). https://milkweedusa.com/species/heartleaf-milkweed/ --- # Largeflower Milkweed (Asclepias connivens) > A wet pine savanna milkweed with unusually large, pale green, cup-shaped flowers whose hoods lean inward and meet over the center, a structure found nowhere else in the genus. Source: https://milkweedusa.com/species/largeflower-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A wet pine savanna milkweed with unusually large, pale green, cup-shaped flowers whose hoods lean inward and meet over the center, a structure found nowhere else in the genus. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias connivens Baldwin | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Largeflower Milkweed, Largeflower Green Milkweed | | Status | Native | | Height | 1 ft–2.5 ft | | Spread | 10 in–1.7 ft | | Flower color | green, white | | Bloom period | May to August | | Light | Full sun | | Soil moisture | Wet, Average | | USDA zones | 8-10 | | Leaf arrangement | opposite | | Leaf shape | oblong | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 2 | | US states recorded | Alabama, Florida, Georgia, North Carolina, South Carolina | ## Identification - Flowers noticeably large for a green milkweed, with hoods converging over the top. - Few flowers per cluster, giving an open, sculptural look. - Restricted to wet pine flatwoods and savanna on the coastal plain. ## Ecology A specialist of intact, regularly burned wet savanna, an increasingly rare habitat. ## Growing Not in general cultivation. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94179-1 - GBIF: https://www.gbif.org/species/7947055 - iNaturalist: https://www.inaturalist.org/taxa/158735 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_connivens - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20connivens.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20connivens ## Photographs - Largeflower Milkweed photographed in Franklin County, US-FL, US (Jay Horn, CC BY 4.0): https://www.inaturalist.org/observations/26299840 - Largeflower Milkweed photographed in Florida, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/311122756 - Largeflower Milkweed photographed in Apalachicola National Forest, Bristol, FL, US (Jason K., CC BY 4.0): https://www.inaturalist.org/observations/91073547 - Largeflower Milkweed photographed in Liberty County, FL, USA (Jody Shugart, CC BY 4.0): https://www.inaturalist.org/observations/222353397 - Largeflower Milkweed photographed in Florida, US (evangrimes, CC BY 4.0): https://www.inaturalist.org/observations/121688679 - Largeflower Milkweed photographed in the wild (Michelle Sevcovas, CC BY 4.0): https://www.inaturalist.org/observations/123444942 - Largeflower Milkweed photographed in Florida, US (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/92318699 - Largeflower Milkweed photographed in Apalachicola, FL 32320, USA (Scott Allen Davis, CC BY 4.0): https://www.inaturalist.org/observations/226734995 ## How to cite Milkweed USA. (2026). Largeflower Milkweed (Asclepias connivens). https://milkweedusa.com/species/largeflower-milkweed/ --- # Lemmon’s Milkweed (Asclepias lemmonii) > A slim sky-island milkweed of shaded canyon bottoms in southeastern Arizona and southwestern New Mexico, with small green flowers flushed purple, appearing after the summer rains. Source: https://milkweedusa.com/species/lemmons-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A slim sky-island milkweed of shaded canyon bottoms in southeastern Arizona and southwestern New Mexico, with small green flowers flushed purple, appearing after the summer rains. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias lemmonii A. Gray | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Lemmon’s Milkweed | | Status | Native | | Height | 8 in–2 ft | | Spread | 8 in–1.5 ft | | Flower color | green, purple | | Bloom period | July to September | | Light | Part shade, Full sun | | Soil moisture | Dry, Average | | USDA zones | 7-10 | | Leaf arrangement | opposite | | Leaf shape | lanceolate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Arizona, New Mexico | ## Identification - Slender stems in moist canyon shade rather than open desert. - Small green flowers tinged with dull purple, few per cluster. - Restricted to the higher sky-island ranges near the Mexican border. ## Ecology A borderland species at the northern edge of a largely Mexican distribution, used by queens as well as monarchs. ## Growing Not in cultivation. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94393-1 - GBIF: https://www.gbif.org/species/3170287 - iNaturalist: https://www.inaturalist.org/taxa/158746 - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20lemmonii.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20lemmonii ## Photographs - Lemmon’s Milkweed photographed in Huásabas, Son., México (M. Socorro González Elizondo, CC BY-SA 4.0): https://www.inaturalist.org/observations/202911704 - Lemmon’s Milkweed photographed in 80623 Badiraguato Sin., México (Public domain (CC0), CC0): https://www.inaturalist.org/observations/167434125 - Lemmon’s Milkweed photographed in Santa Cruz County, AZ, USA (Sue Carnahan, CC BY 4.0): https://www.inaturalist.org/observations/257931049 - Lemmon’s Milkweed photographed in Arizona, United States (Katja Schulz, CC BY 4.0): https://www.inaturalist.org/observations/8926073 - Lemmon’s Milkweed photographed in Cochise County, AZ, USA (Rachel Stringham, CC BY 4.0): https://www.inaturalist.org/observations/244828918 - Lemmon’s Milkweed photographed in 31993 Chih., México (Tereka Lasso, CC BY-SA 4.0): https://www.inaturalist.org/observations/126019696 - Lemmon’s Milkweed photographed in Cochise County, AZ, USA (Jeremiah Degenhardt, CC BY 4.0): https://www.inaturalist.org/observations/128144879 - Lemmon’s Milkweed photographed in E Carr Canyon Rd, Hereford, AZ, US (CK2AZ, CC BY 4.0): https://www.inaturalist.org/observations/235718984 ## How to cite Milkweed USA. (2026). Lemmon’s Milkweed (Asclepias lemmonii). https://milkweedusa.com/species/lemmons-milkweed/ --- # Longhood Milkweed (Asclepias macrotis) > A slender limestone-canyon milkweed of west Texas, New Mexico and southern Colorado, with thread-like leaves and small pale flowers whose unusually long hoods give it its name. Source: https://milkweedusa.com/species/longhood-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A slender limestone-canyon milkweed of west Texas, New Mexico and southern Colorado, with thread-like leaves and small pale flowers whose unusually long hoods give it its name. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias macrotis Torr. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Longhood Milkweed | | Status | Native | | Height | 8 in–1.7 ft | | Spread | 10 in–1.7 ft | | Flower color | green, cream | | Bloom period | April to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 6-9 | | Leaf arrangement | opposite | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Arizona, Colorado, New Mexico, Texas | ## Identification - Very long, projecting hoods on small greenish flowers. - Wiry sprawling stems with thread-fine opposite leaves. - Restricted to limestone outcrops and rocky canyon slopes. ## Ecology A localised desert-canyon species of limited but real value to monarchs and queens moving through the Southwest. ## Growing Not in cultivation. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94433-1 - GBIF: https://www.gbif.org/species/3170310 - iNaturalist: https://www.inaturalist.org/taxa/121660 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_macrotis - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20macrotis.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20macrotis ## Photographs - Asclepias macrotis - Michelle W 02 (Michelle W. (鍾偉瑋), CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_macrotis_-_Michelle_W_02.jpg - Asclepias macrotis - Michelle W 01 (Michelle W. (鍾偉瑋), CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_macrotis_-_Michelle_W_01.jpg - Asclepias macrotis - Michelle W 03 (Michelle W. (鍾偉瑋), CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_macrotis_-_Michelle_W_03.jpg - Asclepias macrotis - Michelle W 04 (Michelle W. (鍾偉瑋), CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_macrotis_-_Michelle_W_04.jpg - Asclepias macrotis - Michelle W 05 (Michelle W. (鍾偉瑋), CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_macrotis_-_Michelle_W_05.jpg - Asclepias macrotis - Michelle W 06 (Michelle W. (鍾偉瑋), CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_macrotis_-_Michelle_W_06.jpg - Asclepias macrotis - Michelle W 07 (Michelle W. (鍾偉瑋), CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_macrotis_-_Michelle_W_07.jpg - Asclepias macrotis - Michelle W 09 (Michelle W. (鍾偉瑋), CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_macrotis_-_Michelle_W_09.jpg ## How to cite Milkweed USA. (2026). Longhood Milkweed (Asclepias macrotis). https://milkweedusa.com/species/longhood-milkweed/ --- # Longleaf Milkweed (Asclepias longifolia) > A slim coastal plain milkweed of damp pine savanna, with long narrow leaves and greenish-white flowers heavily washed in purple, borne in nodding clusters from the upper leaf axils. Source: https://milkweedusa.com/species/longleaf-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A slim coastal plain milkweed of damp pine savanna, with long narrow leaves and greenish-white flowers heavily washed in purple, borne in nodding clusters from the upper leaf axils. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias longifolia Michx. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Longleaf Milkweed | | Status | Native | | Height | 1 ft–2.5 ft | | Spread | 8 in–1.3 ft | | Flower color | green, purple, white | | Bloom period | April to July | | Light | Full sun | | Soil moisture | Wet, Average | | USDA zones | 7-10 | | Leaf arrangement | opposite | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Fibrous, clump-forming and easy to move | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 2 | | US states recorded | Alabama, Arkansas, Delaware, Florida, Georgia, Louisiana, Maryland, Mississippi, North Carolina, New Jersey, South Carolina, Texas, Virginia | ## Identification - Long, narrow, closely spaced opposite leaves. - Flowers green-white strongly tinted purple, in drooping axillary clusters. - Moist pine savanna and flatwoods. ## Ecology Another fire-dependent coastal plain species with a shrinking habitat base. ## Growing Seldom cultivated. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:329558-2 - GBIF: https://www.gbif.org/species/3170230 - iNaturalist: https://www.inaturalist.org/taxa/158748 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_longifolia - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20longifolia.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20longifolia ## Photographs - Asclepias longifolia imported from iNaturalist photo 30402035 on 8 February 2020 ((c) Jody Shugart, some rights reserved (CC BY), CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_longifolia_imported_from_iNaturalist_photo_30402035_on_8_February_2020.jpg - Asclepias longifolia imported from iNaturalist photo 30402038 on 8 February 2020 ((c) Jody Shugart, some rights reserved (CC BY), CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_longifolia_imported_from_iNaturalist_photo_30402038_on_8_February_2020.jpg - Asclepias incarnata 25zz (Photo by David J. Stang, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_incarnata_25zz.jpg - Longleaf Milkweed photographed in Jackson County, MS, USA (Lauren McLaurin, CC BY 4.0): https://www.inaturalist.org/observations/25280424 - Longleaf Milkweed photographed in Wewahitchka, FL 32465, USA (Scott Allen Davis, CC BY 4.0): https://www.inaturalist.org/observations/176522012 - Longleaf Milkweed photographed in Punta Gorda, FL 33982, USA (Jay Horn, CC BY 4.0): https://www.inaturalist.org/observations/26570764 - Longleaf Milkweed photographed in Georgia, US (Jessica, CC BY 4.0): https://www.inaturalist.org/observations/177674708 - Longleaf Milkweed photographed in North Carolina, US (harrier, CC BY 4.0): https://www.inaturalist.org/observations/223460508 ## How to cite Milkweed USA. (2026). Longleaf Milkweed (Asclepias longifolia). https://milkweedusa.com/species/longleaf-milkweed/ --- # Mahogany Milkweed (Asclepias hypoleuca) > A handsome sky-island milkweed whose broad leaves are conspicuously white beneath, carrying nodding clusters of deep mahogany-red flowers with pale cream hoods through the monsoon season. Source: https://milkweedusa.com/species/mahogany-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A handsome sky-island milkweed whose broad leaves are conspicuously white beneath, carrying nodding clusters of deep mahogany-red flowers with pale cream hoods through the monsoon season. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias hypoleuca (A. Gray) Woodson | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Mahogany Milkweed, White-leaf Milkweed | | Status | Native | | Height | 1 ft–2.5 ft | | Spread | 1 ft–2 ft | | Flower color | maroon, cream | | Bloom period | June to September | | Light | Part shade, Full sun | | Soil moisture | Dry | | USDA zones | 6-9 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, New Mexico | ## Identification - Leaf undersides distinctly white or chalky, which is the giveaway character. - Flowers rich mahogany-brown to maroon with contrasting cream hoods. - Oak woodland and canyon slopes in the Arizona and New Mexico mountains. ## Ecology A monsoon-season host and nectar source in the borderland sky islands, where it often grows alongside Lemmon’s milkweed. ## Growing Occasionally offered by specialist Southwest nurseries. Needs sharp drainage and light shade at low elevation. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21202-2 - GBIF: https://www.gbif.org/species/3170298 - iNaturalist: https://www.inaturalist.org/taxa/158742 - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20hypoleuca.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20hypoleuca ## Photographs - Mahogany Milkweed photographed in Barfoot Park, Arizona (Sam Kieschnick, CC BY 4.0): https://www.inaturalist.org/observations/8058885 - Mahogany Milkweed photographed in Coronado National Forest, Rio Rico, AZ, US (Aaron Liston, CC BY 4.0): https://www.inaturalist.org/observations/29778460 - Mahogany Milkweed photographed in Rustler Park Chiricahua mtns Cochise county Arizona (Gordon C. Snelling, CC BY 4.0): https://www.inaturalist.org/observations/2464049 - Mahogany Milkweed photographed in Cochise County, AZ, USA (Sue Carnahan, CC BY 4.0): https://www.inaturalist.org/observations/272059626 - Mahogany Milkweed photographed in Coronado National Forest, Willcox, AZ, US (Katherine Parys, CC BY 4.0): https://www.inaturalist.org/observations/93219331 - Mahogany Milkweed photographed in Butterfly Trail, Mt. Lemmon, Pima County, AZ, USA (Ken-ichi Ueda, CC BY 4.0): https://www.inaturalist.org/observations/28269048 - Mahogany Milkweed photographed in Pima County, US-AZ, US (Mike Ostrowski, CC BY-SA 4.0): https://www.inaturalist.org/observations/371345086 - Mahogany Milkweed photographed in Sierra Vista Southeast, AZ, USA (Alina Martin, CC BY 4.0): https://www.inaturalist.org/observations/178977979 ## How to cite Milkweed USA. (2026). Mahogany Milkweed (Asclepias hypoleuca). https://milkweedusa.com/species/mahogany-milkweed/ --- # Mead’s Milkweed (Asclepias meadii) > A federally threatened tallgrass-prairie milkweed with a single nodding cluster of greenish-cream flowers on a slim glaucous stem. It survives almost entirely on hay meadows and prairie remnants that have never been plowed. Source: https://milkweedusa.com/species/meads-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A federally threatened tallgrass-prairie milkweed with a single nodding cluster of greenish-cream flowers on a slim glaucous stem. It survives almost entirely on hay meadows and prairie remnants that have never been plowed. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias meadii Torr. ex A. Gray | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Mead’s Milkweed | | Status | Native; rare or legally protected in part of its range | | Height | 1 ft–2 ft | | Spread | 8 in–1.2 ft | | Flower color | green, cream | | Bloom period | May to June | | Light | Full sun | | Soil moisture | Average, Dry | | USDA zones | 4-7 | | Leaf arrangement | opposite | | Leaf shape | oblong | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 60 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Iowa, Illinois, Kansas, Missouri | ## Identification - One drooping flower cluster per stem, pale green-cream. - Smooth blue-green leaves in widely spaced opposite pairs. - Found only on high-quality unplowed tallgrass prairie. ## Ecology Listed as Threatened under the US Endangered Species Act. Mid-summer haying prevents seed set, and most surviving populations are single clones that cannot self-pollinate. ## Growing Legally protected. Do not collect seed, plants or cuttings. Report sightings to your state heritage program. ## Cautions Federally threatened. Collection is prohibited. ## Questions **Is any milkweed endangered?** Yes. Mead’s milkweed (A. meadii) is federally listed as Threatened, and Welsh’s milkweed (A. welshii) is listed as Threatened in Utah and Arizona. Many more species, purple milkweed, red milkweed and wheel milkweed among them, are listed at state level. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94445-1 - GBIF: https://www.gbif.org/species/3170259 - iNaturalist: https://www.inaturalist.org/taxa/158749 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_meadii - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20meadii.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20meadii ## Photographs - Mead's Milkweed (Asclepias meadii) - Flickr - Jay Sturner (Jay Sturner from USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Mead%27s_Milkweed_(Asclepias_meadii)_-_Flickr_-_Jay_Sturner.jpg - Mead's Milkweed (Asclepias meadii) - Flickr - Jay Sturner (1) (Jay Sturner from USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Mead%27s_Milkweed_(Asclepias_meadii)_-_Flickr_-_Jay_Sturner_(1).jpg - Mead's Milkweed (Asclepias meadii) - Flickr - Jay Sturner (2) (Jay Sturner from USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Mead%27s_Milkweed_(Asclepias_meadii)_-_Flickr_-_Jay_Sturner_(2).jpg - Mead's Milkweed (Asclepias meadii) - Flickr - Jay Sturner (3) (Jay Sturner from USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Mead%27s_Milkweed_(Asclepias_meadii)_-_Flickr_-_Jay_Sturner_(3).jpg - Mead's Milkweed (Asclepias meadii) - Flickr - Jay Sturner (4) (Jay Sturner from USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Mead%27s_Milkweed_(Asclepias_meadii)_-_Flickr_-_Jay_Sturner_(4).jpg - Mead's Milkweed (Asclepias meadii) - Flickr - Jay Sturner (5) (Jay Sturner from USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Mead%27s_Milkweed_(Asclepias_meadii)_-_Flickr_-_Jay_Sturner_(5).jpg - Mead's Milkweed (Asclepias meadii) - Flickr - Jay Sturner (6) (Jay Sturner from USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Mead%27s_Milkweed_(Asclepias_meadii)_-_Flickr_-_Jay_Sturner_(6).jpg - Asclepiasmeadii (Jason Sturner 72, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepiasmeadii.jpg ## How to cite Milkweed USA. (2026). Mead’s Milkweed (Asclepias meadii). https://milkweedusa.com/species/meads-milkweed/ --- # Michaux’s Milkweed (Asclepias michauxii) > A slender pine-flatwoods milkweed of the coastal plain with very narrow leaves and small dusky pink-green flowers, dependent on regular fire to keep its habitat open. Source: https://milkweedusa.com/species/michauxs-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A slender pine-flatwoods milkweed of the coastal plain with very narrow leaves and small dusky pink-green flowers, dependent on regular fire to keep its habitat open. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias michauxii Decne. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Michaux’s Milkweed, Southern Milkweed | | Status | Native | | Height | 8 in–1.7 ft | | Spread | 8 in–1.3 ft | | Flower color | pink, green | | Bloom period | April to July | | Light | Full sun | | Soil moisture | Dry, Average | | USDA zones | 7-10 | | Leaf arrangement | opposite | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 2 | | US states recorded | Alabama, Florida, Georgia, North Carolina, South Carolina | ## Identification - Narrow, almost grass-like opposite leaves on a short upright stem. - Small flowers in a loose terminal cluster, dull pink over green. - Found in frequently burned pine flatwoods and savanna. ## Ecology A fire-dependent species that declines quickly where prescribed burning stops. ## Growing Rarely cultivated. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94453-1 - GBIF: https://www.gbif.org/species/3170238 - iNaturalist: https://www.inaturalist.org/taxa/158750 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_michauxii - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20michauxii.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20michauxii ## Photographs - Asclepias michauxii in flower (Kim, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_michauxii_in_flower.jpg - Michaux’s Milkweed photographed in SW Forest Road 180, Bristol, FL, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/351433539 - Michaux’s Milkweed photographed in Covington County, AL, USA (Brian Finzel, CC BY-SA 4.0): https://www.inaturalist.org/observations/195444580 - Michaux’s Milkweed photographed in Jackson County, MS, USA (Lauren McLaurin, CC BY 4.0): https://www.inaturalist.org/observations/25280425 - Michaux’s Milkweed photographed in Liberty County, GA, USA (Celeste Ray, CC BY 4.0): https://www.inaturalist.org/observations/37779422 - Michaux’s Milkweed photographed in Liberty County, FL, USA (James (Jim) Duggan, CC BY-SA 4.0): https://www.inaturalist.org/observations/160666766 - Michaux’s Milkweed photographed in Cape San Blas, FL 32456, USA (Scott Allen Davis, CC BY 4.0): https://www.inaturalist.org/observations/208842498 - Michaux’s Milkweed photographed in Brooklyn, MS 39425, USA (Shawn Harris, CC BY 4.0): https://www.inaturalist.org/observations/214102492 ## How to cite Milkweed USA. (2026). Michaux’s Milkweed (Asclepias michauxii). https://milkweedusa.com/species/michauxs-milkweed/ --- # Mojave Milkweed (Asclepias nyctaginifolia) > A low desert milkweed with broad soft leaves like a four-o’clock plant and nodding clusters of green-cream flowers, scattered across sandy flats and washes in the Mojave and northern Sonoran deserts. Source: https://milkweedusa.com/species/mojave-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A low desert milkweed with broad soft leaves like a four-o’clock plant and nodding clusters of green-cream flowers, scattered across sandy flats and washes in the Mojave and northern Sonoran deserts. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias nyctaginifolia A. Gray | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Mojave Milkweed, Four-o’clock Milkweed | | Status | Native | | Height | 6 in–1.5 ft | | Spread | 1 ft–2 ft | | Flower color | green, cream | | Bloom period | April to June | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 7-10 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 2 | | US states recorded | Arizona, New Mexico, Nevada, Utah | ## Identification - Broad, soft, wavy-margined leaves close to the ground. - Nodding clusters of pale green flowers on short stalks. - Sandy desert flats, washes and roadside margins. ## Ecology A spring desert host used during northward monarch and queen movement. ## Growing Not in cultivation. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94494-1 - GBIF: https://www.gbif.org/species/3170320 - iNaturalist: https://www.inaturalist.org/taxa/62294 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_nyctaginifolia - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20nyctaginifolia.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20nyctaginifolia ## Photographs - Asclepias nyctaginifolia (Mike, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_nyctaginifolia.jpg - South side of Ute Lake - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:South_side_of_Ute_Lake_-_Flickr_-_aspidoscelis.jpg - Near Caracita Creek - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Near_Caracita_Creek_-_Flickr_-_aspidoscelis.jpg - Mojave Milkweed photographed in Crown King, AZ 86343, USA (Marie Domokos, CC BY 4.0): https://www.inaturalist.org/observations/321743188 - Mojave Milkweed photographed in Santa Cruz County, AZ, USA (Sue Carnahan, CC BY 4.0): https://www.inaturalist.org/observations/258040780 - Mojave Milkweed photographed in Finley Tank Rd, Elgin, AZ, US (Brad Grimm, CC BY 4.0): https://www.inaturalist.org/observations/30904368 - Mojave Milkweed photographed in 33.369 -108.116 (Public domain (CC0), CC0): https://www.inaturalist.org/observations/9256957 - Mojave Milkweed photographed in Agua Prieta, MX-SO, MX (Jonathan Rodriguez, CC BY 4.0): https://www.inaturalist.org/observations/56749702 ## How to cite Milkweed USA. (2026). Mojave Milkweed (Asclepias nyctaginifolia). https://milkweedusa.com/species/mojave-milkweed/ --- # Narrowleaf Milkweed (Asclepias fascicularis) > The workhorse milkweed of the Pacific states and the backbone of western monarch recovery planting. Slim whorls of narrow leaves, dense clusters of small greenish-white flowers flushed pink, and an ability to shrug off a rainless California summer. Source: https://milkweedusa.com/species/narrowleaf-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary The workhorse milkweed of the Pacific states and the backbone of western monarch recovery planting. Slim whorls of narrow leaves, dense clusters of small greenish-white flowers flushed pink, and an ability to shrug off a rainless California summer. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias fascicularis Decne. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Narrowleaf Milkweed, Mexican Whorled Milkweed, Narrow-leaved Milkweed | | Status | Native | | Height | 2 ft–4 ft | | Spread | 1.5 ft–3 ft | | Flower color | white, pink, green | | Bloom period | May to September | | Light | Full sun | | Soil moisture | Dry, Average | | USDA zones | 6-10 | | Leaf arrangement | whorled | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 5 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 4 | | US states recorded | Arizona, California, Idaho, Nevada, Oregon, Utah, Washington | ## Identification - Leaves narrow and often in whorls of three to five, but wider and softer than eastern whorled milkweed. - Flower clusters are dense and rounded, greenish-white with a dull rose tinge. - Stems slender, usually several from one crown, smooth or nearly so. - Widely branched at the top when growing well. ## Ecology The primary larval host for the western monarch population through California’s Central Valley and foothills. Tolerates the long dry summer that kills more mesic milkweeds, and re-sprouts vigorously after being grazed or mown. ## Growing The right milkweed for a California, Oregon or Nevada garden. Deeply drought-tolerant once established, spreads slowly by rhizome, and goes summer-dormant if left completely dry. Sow in the fall to use winter rains, or stratify for a month and sow in spring. ## Cautions Like other narrow-leaved milkweeds it is toxic to grazing stock in quantity, and it is the species most often implicated in western livestock poisoning. ## Questions **What is the best milkweed to plant in California?** Narrowleaf milkweed (A. fascicularis) for most of the state, showy milkweed (A. speciosa) in the north and at elevation, and heartleaf or California milkweed in specific foothill habitats. Avoid tropical milkweed entirely, because California is frost-free enough to sustain year-round breeding. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94272-1 - GBIF: https://www.gbif.org/species/3170291 - iNaturalist: https://www.inaturalist.org/taxa/56851 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_fascicularis - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20fascicularis.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20fascicularis ## Photographs - Asclepias fascicularis flowers 2003-06-05 (No machine-readable author provided. Curtis Clark assumed (based on copyright claims)., CC BY-SA 2.5): https://commons.wikimedia.org/wiki/File:Asclepias_fascicularis_flowers_2003-06-05.jpg - Asclepias fascicularis, Narrowleaf Milkweed (glmory, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_fascicularis,_Narrowleaf_Milkweed.jpg - Narrowleaf Milkweed - Asclepias fascicularis (28595688567) (Björn S..., CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Narrowleaf_Milkweed_-_Asclepias_fascicularis_(28595688567).jpg - Narrowleaf Milkweed - Asclepias fascicularis (28595012917) (Björn S..., CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Narrowleaf_Milkweed_-_Asclepias_fascicularis_(28595012917).jpg - Narrowleaf Milkweed - Asclepias fascicularis (28595687447) (Björn S..., CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Narrowleaf_Milkweed_-_Asclepias_fascicularis_(28595687447).jpg - Narrowleaf Milkweed - Asclepias fascicularis (28595689207) (Björn S..., CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Narrowleaf_Milkweed_-_Asclepias_fascicularis_(28595689207).jpg - Narrowleaf Milkweed - Asclepias fascicularis (43433980632) (Björn S..., CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Narrowleaf_Milkweed_-_Asclepias_fascicularis_(43433980632).jpg - Narrowleaf Milkweed - Asclepias fascicularis (43436024432) (Björn S..., CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Narrowleaf_Milkweed_-_Asclepias_fascicularis_(43436024432).jpg ## How to cite Milkweed USA. (2026). Narrowleaf Milkweed (Asclepias fascicularis). https://milkweedusa.com/species/narrowleaf-milkweed/ --- # Nodding Milkweed (Asclepias glaucescens) > A stout borderland milkweed with thick blue-gray leaves and heavy nodding clusters of greenish-white flowers, growing in oak woodland and canyon grassland in the Arizona and New Mexico sky islands. Source: https://milkweedusa.com/species/nodding-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A stout borderland milkweed with thick blue-gray leaves and heavy nodding clusters of greenish-white flowers, growing in oak woodland and canyon grassland in the Arizona and New Mexico sky islands. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias glaucescens Kunth | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Nodding Milkweed, Glaucous Milkweed | | Status | Native | | Height | 1 ft–3 ft | | Spread | 1 ft–2 ft | | Flower color | green, white | | Bloom period | June to September | | Light | Part shade, Full sun | | Soil moisture | Dry, Average | | USDA zones | 6-10 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, New Mexico | ## Identification - Thick, waxy, distinctly blue-gray (glaucous) leaves. - Flower clusters nod downward on stout stalks. - Sturdier and broader-leaved than the other borderland species. ## Ecology A monsoon-season host that provides substantial leaf area at a time when the desert below is exhausted. ## Growing Rarely offered; needs sharp drainage and summer moisture. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94322-1 - GBIF: https://www.gbif.org/species/3170302 - iNaturalist: https://www.inaturalist.org/taxa/158740 - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20glaucescens.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20glaucescens ## Photographs - Asclepias glaucescens (Edgar p miller, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_glaucescens.jpg - Asclepias glaucescens (7554335692) (Tyrrhium, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_glaucescens_(7554335692).jpg - Asclepias glaucescens1 (Bodofzt, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_glaucescens1.jpg - Nodding Milkweed photographed in Acámbaro, Guanajuato, Mexico (Oscar Alejandro Morales Juárez, CC BY-SA 4.0): https://www.inaturalist.org/observations/262986153 - Nodding Milkweed photographed in California, Reserva de la Biosfera La Sepultura, Chiapas (Neptalí Ramírez Marcial, CC BY 4.0): https://www.inaturalist.org/observations/3473008 - Nodding Milkweed photographed in 68258 Oax., México (Ricardo Betancourt Sánchez, CC BY 4.0): https://www.inaturalist.org/observations/227617231 - Nodding Milkweed photographed in 3ro, 70830 Santa Catarina Cuixtla, Oax., México (Carlos Domínguez-Rodríguez, CC BY 4.0): https://www.inaturalist.org/observations/151786056 - Nodding Milkweed photographed in Monte Albán, Oax., Mexico (Corey Farwell, CC BY 4.0): https://www.inaturalist.org/observations/261928314 ## How to cite Milkweed USA. (2026). Nodding Milkweed (Asclepias glaucescens). https://milkweedusa.com/species/nodding-milkweed/ --- # Oval-leaf Milkweed (Asclepias ovalifolia) > A compact northern-prairie milkweed under two feet tall, with neat oval leaves and small creamy-white flower clusters, found on sandy prairie and open oak savanna from Michigan to Montana. Source: https://milkweedusa.com/species/ovalleaf-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A compact northern-prairie milkweed under two feet tall, with neat oval leaves and small creamy-white flower clusters, found on sandy prairie and open oak savanna from Michigan to Montana. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias ovalifolia Decne. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Oval-leaf Milkweed, Dwarf Milkweed | | Status | Native | | Height | 8 in–1.7 ft | | Spread | 1 ft–2.5 ft | | Flower color | white, green | | Bloom period | June to July | | Light | Full sun, Part shade | | Soil moisture | Dry, Average | | USDA zones | 3-7 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 60 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Iowa, Illinois, Michigan, Minnesota, Montana, North Dakota, Nebraska, South Dakota, Wisconsin | ## Identification - Short stature with evenly spaced oval opposite leaves, downy beneath. - One or two small terminal clusters of creamy white to greenish flowers. - Northern prairie, sand savanna and open jack pine barrens. ## Ecology A useful monarch host in the northern breeding range and a good early-summer nectar plant on sandy prairie. ## Growing A well-behaved small milkweed for northern gardens, spreading slowly by rhizome. Needs a long cold stratification. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94507-1 - GBIF: https://www.gbif.org/species/3170264 - iNaturalist: https://www.inaturalist.org/taxa/47905 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_ovalifolia - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20ovalifolia.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20ovalifolia ## Photographs - Ovalleaf Milkweed (Asclepias ovalifolia) (USFWS Mountain Prairie, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Ovalleaf_Milkweed_(Asclepias_ovalifolia).jpg - Oval-leaf milkweed (19054174765) (Justin Meissen from St Paul, United States, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Oval-leaf_milkweed_(19054174765).jpg - Some kind of desert flower (14480035108) (waferboard, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Some_kind_of_desert_flower_(14480035108).png - Oval-leaf Milkweed on Mundt Lake WPA (36093654383) (USFWS Mountain-Prairie, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Oval-leaf_Milkweed_on_Mundt_Lake_WPA_(36093654383).jpg - Oval-leaf Milkweed photographed in Leola, SD, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/270557637 - Oval-leaf Milkweed photographed in Sibley, ND, USA (Esben Kjaer, CC BY 4.0): https://www.inaturalist.org/observations/123178170 - Oval-leaf Milkweed photographed in Riding Mountain National Park, Lake Audy, MB, CA (Sean Frey, CC BY 4.0): https://www.inaturalist.org/observations/85844657 - Oval-leaf Milkweed photographed in Beaver Creek Conservation Area, Corman Park, SK, CA (Dustin Snider, CC BY 4.0): https://www.inaturalist.org/observations/223024824 ## How to cite Milkweed USA. (2026). Oval-leaf Milkweed (Asclepias ovalifolia). https://milkweedusa.com/species/ovalleaf-milkweed/ --- # Pallid Milkweed (Asclepias cryptoceras) > A jewel of the Great Basin: a low sprawling rosette of round, waxy, blue-green leaves surrounding cream flowers with vivid rose-pink hoods, blooming in spring on barren clay and shale slopes where nothing else grows. Source: https://milkweedusa.com/species/pallid-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A jewel of the Great Basin: a low sprawling rosette of round, waxy, blue-green leaves surrounding cream flowers with vivid rose-pink hoods, blooming in spring on barren clay and shale slopes where nothing else grows. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias cryptoceras S. Watson | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Pallid Milkweed, Jewelled Milkweed, Humboldt Mountain Milkweed | | Status | Native | | Height | 4 in–1 ft | | Spread | 1 ft–2 ft | | Flower color | cream, pink | | Bloom period | April to June | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 4-8 | | Leaf arrangement | opposite | | Leaf shape | orbicular | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 60 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, California, Colorado, Idaho, New Mexico, Nevada, Oregon, Utah, Washington, Wyoming | ## Identification - Prostrate habit: the plant lies flat on the ground in a neat circle. - Leaves nearly circular, thick, smooth and glaucous blue-green. - Flowers cream with startlingly pink or purple hoods, unlike any other milkweed. ## Ecology A specialist of harsh desert substrates. Little used by monarchs because it goes dormant by early summer, but botanically one of the most remarkable plants in the genus. ## Growing For experienced rock gardeners only. Needs a mineral, unwatered, perfectly drained site and a long cold stratification. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94206-1 - GBIF: https://www.gbif.org/species/3170263 - iNaturalist: https://www.inaturalist.org/taxa/62297 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_cryptoceras - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20cryptoceras.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20cryptoceras ## Photographs - Asclepias cryptoceras ssp. davisii plant-4-12-04 (Thayne Tuason, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_cryptoceras_ssp._davisii_plant-4-12-04.jpg - Asclepias cryptoceras (Mary Winter, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_cryptoceras.jpg - Asclepias cryptoceras ssp. davisii fruit-5-12-04 (Thayne Tuason, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_cryptoceras_ssp._davisii_fruit-5-12-04.jpg - Asclepias cryptoceras ssp. davisii-4-12-04 (Thayne Tuason, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_cryptoceras_ssp._davisii-4-12-04.jpg - Cow cabbage, Asclepias cryptoceras (15458150903) (Jim Morefield from Nevada, USA, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Cow_cabbage,_Asclepias_cryptoceras_(15458150903).jpg - Cow cabbage, Asclepias cryptoceras (49068243972) (Jim Morefield from Nevada, USA, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Cow_cabbage,_Asclepias_cryptoceras_(49068243972).jpg - Cow cabbage, Asclepias cryptoceras (49068037891) (Jim Morefield from Nevada, USA, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Cow_cabbage,_Asclepias_cryptoceras_(49068037891).jpg - Asclepias cryptoceras - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_cryptoceras_-_Flickr_-_aspidoscelis.jpg ## How to cite Milkweed USA. (2026). Pallid Milkweed (Asclepias cryptoceras). https://milkweedusa.com/species/pallid-milkweed/ --- # Pineland Milkweed (Asclepias obovata) > A modest greenish-yellow-flowered milkweed of dry southeastern pinelands and sandy roadsides, with softly hairy paddle-shaped leaves. Source: https://milkweedusa.com/species/pineland-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A modest greenish-yellow-flowered milkweed of dry southeastern pinelands and sandy roadsides, with softly hairy paddle-shaped leaves. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias obovata Elliott | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Pineland Milkweed, Obovate Milkweed | | Status | Native | | Height | 1 ft–2.5 ft | | Spread | 1 ft–2 ft | | Flower color | green, yellow | | Bloom period | June to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 7-9 | | Leaf arrangement | opposite | | Leaf shape | oblong | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 2 | | US states recorded | Alabama, Florida, Georgia, Louisiana, Mississippi, South Carolina, Texas | ## Identification - Leaves broadest above the middle, blunt-tipped and downy. - Greenish-yellow flowers in small axillary clusters. - Dry sandy pine woods and their margins. ## Ecology A summer-blooming host in southern pine country, used by monarchs and queens. ## Growing Occasionally offered by southeastern native nurseries. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:329559-2 - GBIF: https://www.gbif.org/species/3170299 - iNaturalist: https://www.inaturalist.org/taxa/158752 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_obovata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20obovata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20obovata ## Photographs - Asclepias obovata in bloom (Turner Brockman, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_obovata_in_bloom.jpg - Asclepias obovata (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_obovata.jpg - Pineland Milkweed photographed in E.O. Siecke State Forest, Newton County, TX, USA (Laura Clark, CC BY 4.0): https://www.inaturalist.org/observations/7620312 - Pineland Milkweed photographed in Lake City, FL, US (meflowers900, CC BY 4.0): https://www.inaturalist.org/observations/137292662 - Pineland Milkweed photographed in Texas, US (Ayla, CC BY 4.0): https://www.inaturalist.org/observations/45517813 - Pineland Milkweed photographed in Texas, US (Alison Northup, CC BY 4.0): https://www.inaturalist.org/observations/62449450 - Pineland Milkweed photographed in Screven County, GA, USA (Public domain (CC0), CC0): https://www.inaturalist.org/observations/133100472 - Pineland Milkweed photographed in Jackson County, MS, USA (Lauren McLaurin, CC BY 4.0): https://www.inaturalist.org/observations/17478801 ## How to cite Milkweed USA. (2026). Pineland Milkweed (Asclepias obovata). https://milkweedusa.com/species/pineland-milkweed/ --- # Pineneedle Milkweed (Asclepias linaria) > A shrubby, evergreen-looking milkweed densely clothed in soft needle-like leaves, resembling a small conifer until it produces its white flower clusters. A favorite of desert gardeners in Arizona and New Mexico. Source: https://milkweedusa.com/species/pineneedle-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A shrubby, evergreen-looking milkweed densely clothed in soft needle-like leaves, resembling a small conifer until it produces its white flower clusters. A favorite of desert gardeners in Arizona and New Mexico. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias linaria Cav. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Pineneedle Milkweed, Needle-leaf Milkweed | | Status | Native | | Height | 1.5 ft–4 ft | | Spread | 1.5 ft–3 ft | | Flower color | white, cream | | Bloom period | March to October | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 8-11 | | Leaf arrangement | alternate | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, New Mexico, Texas | ## Identification - Dense, soft, pine-needle foliage on a woody-based shrubby plant. - Small white flowers in tight rounded clusters at the branch tips. - Retains foliage year-round in frost-free areas. ## Ecology A host for monarchs and queens in the Chihuahuan and Sonoran deserts, and a long-season nectar source. ## Growing Widely available in Southwest nurseries and easy in a xeric garden. Full sun, sharp drainage, minimal water. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94400-1 - GBIF: https://www.gbif.org/species/3170270 - iNaturalist: https://www.inaturalist.org/taxa/62295 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_linaria - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20linaria.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20linaria ## Photographs - Inflorescencias del pinillo (Asclepias linaria) (Juan Carlos Fonseca Mata, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Inflorescencias_del_pinillo_(Asclepias_linaria).jpg - Asclepias linaria (Michael Wolf, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_linaria.jpg - Asclepias linaria2 (Michael Wolf, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_linaria2.jpg - Pineneedle Milkweed photographed in Acámbaro, Guanajuato, Mexico (Oscar Alejandro Morales Juárez, CC BY-SA 4.0): https://www.inaturalist.org/observations/123754629 - Pineneedle Milkweed photographed in Hidalgo County, NM, USA (Andrew Tree, CC BY 4.0): https://www.inaturalist.org/observations/208147090 - Pineneedle Milkweed photographed in Dolores Hidalgo Cuna de la Independencia Nacional, Gto., México (Carlos Fonseca, CC BY 4.0): https://www.inaturalist.org/observations/109093214 - Pineneedle Milkweed photographed in Hidalgo County, US-NM, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/66906760 - Pineneedle Milkweed photographed in Santa Cruz County, AZ, USA (Sue Carnahan, CC BY 4.0): https://www.inaturalist.org/observations/248490461 ## How to cite Milkweed USA. (2026). Pineneedle Milkweed (Asclepias linaria). https://milkweedusa.com/species/pineneedle-milkweed/ --- # Pinewoods Milkweed (Asclepias humistrata) > One of the most beautiful foliage plants in the genus: sprawling stems of thick blue-gray clasping leaves veined in bright pink, lying flat on white sand under longleaf pine, topped with pale pink-white flowers in spring. Source: https://milkweedusa.com/species/pinewoods-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary One of the most beautiful foliage plants in the genus: sprawling stems of thick blue-gray clasping leaves veined in bright pink, lying flat on white sand under longleaf pine, topped with pale pink-white flowers in spring. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias humistrata Walter | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Pinewoods Milkweed, Sandhill Milkweed, Purple Milkweed | | Status | Native | | Height | 8 in–2 ft | | Spread | 1.5 ft–3 ft | | Flower color | pink, white | | Bloom period | March to June | | Light | Full sun, Part shade | | Soil moisture | Dry | | USDA zones | 7-10 | | Leaf arrangement | opposite | | Leaf shape | clasping | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | None required | | Monarch value (0-5) | 5 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina | ## Identification - Leaves waxy blue-gray with vivid pink or magenta veins, and unmistakable for it. - Stems lie flat along the ground, radiating from a central taproot. - Grows only in deep dry sand, typically in longleaf pine sandhill. - Blooms very early, from March. ## Ecology The single most important spring monarch host in the Southeast’s sandhill country, and heavily used by the returning migration as it crosses Florida and Georgia. ## Growing Needs pure sand and full sun; impossible in heavy soil. Fresh seed germinates without stratification. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94346-1 - GBIF: https://www.gbif.org/species/3170319 - iNaturalist: https://www.inaturalist.org/taxa/128756 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_humistrata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20humistrata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20humistrata ## Photographs - Asclepias humistrata (ggallice, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_humistrata.jpg - Asclepias humistrata 269716275 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_humistrata_269716275.jpg - Asclepias humistrata 269716282 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_humistrata_269716282.jpg - Asclepias humistrata 269716288 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_humistrata_269716288.jpg - Asclepias humistrata 269716321 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_humistrata_269716321.jpg - Asclepias humistrata 269716298 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_humistrata_269716298.jpg - Asclepias humistrata 269716754 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_humistrata_269716754.jpg - Asclepias humistrata 260660145 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_humistrata_260660145.jpg ## How to cite Milkweed USA. (2026). Pinewoods Milkweed (Asclepias humistrata). https://milkweedusa.com/species/pinewoods-milkweed/ --- # Plains Milkweed (Asclepias pumila) > A knee-high-at-most tuft of fine, almost dill-like foliage carrying tiny cream flowers, scattered across shortgrass prairie from Montana to the Texas Panhandle. Easily mistaken for a grass until it blooms. Source: https://milkweedusa.com/species/plains-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A knee-high-at-most tuft of fine, almost dill-like foliage carrying tiny cream flowers, scattered across shortgrass prairie from Montana to the Texas Panhandle. Easily mistaken for a grass until it blooms. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias pumila (A. Gray) Vail | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Plains Milkweed, Low Milkweed, Dwarf Milkweed | | Status | Native | | Height | 4 in–1 ft | | Spread | 6 in–1.5 ft | | Flower color | white, cream | | Bloom period | June to September | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 3-8 | | Leaf arrangement | alternate | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 3 | | US states recorded | Colorado, Kansas, Montana, North Dakota, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, Wyoming | ## Identification - Rarely over a foot tall, with crowded thread-fine alternate leaves. - Small white to cream flower clusters at the stem tips. - Grows in dense shortgrass and on hard-packed prairie soils where taller milkweeds cannot compete. ## Ecology A genuine shortgrass-prairie specialist. Monarchs use it in the western Great Plains where larger species are absent, and it is important to small native bees on otherwise flowerless rangeland. ## Growing Very drought- and cold-hardy; suited to gravel gardens, green roofs and rock gardens. Spreads slowly by rhizome into a low patch. ## Cautions Narrow-leaved and moderately toxic; a minor component of rangeland poisoning risk. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21273-2 - GBIF: https://www.gbif.org/species/3170288 - iNaturalist: https://www.inaturalist.org/taxa/158756 - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20pumila.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20pumila ## Photographs - Asclepias pumila NPS-1 (Jim Pisarowicz, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_pumila_NPS-1.jpg - Asclepias pumila (14904826353) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_pumila_(14904826353).jpg - Asclepias pumila kz01 (Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_pumila_kz01.jpg - Asclepias pumila kz02 (Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_pumila_kz02.jpg - Asclepias pumila in Oregon (a78a4587-9690-4d14-b8d3-8da6515d2689) (NPS Photo, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_pumila_in_Oregon_(a78a4587-9690-4d14-b8d3-8da6515d2689).jpg - Plains Milkweed photographed in SW Ninth Ave, Amarillo, TX, US (Reid Hardin, CC BY 4.0): https://www.inaturalist.org/observations/88752441 - Plains Milkweed photographed in Burns Ranch, Fort Collins, CO 80526, USA (Alaina Krakowiak, CC BY 4.0): https://www.inaturalist.org/observations/89951321 - Plains Milkweed photographed in Perry Township, SD, USA (Jeff Hansen, CC BY 4.0): https://www.inaturalist.org/observations/295744403 ## How to cite Milkweed USA. (2026). Plains Milkweed (Asclepias pumila). https://milkweedusa.com/species/plains-milkweed/ --- # Poison Milkweed (Asclepias subverticillata) > The whorled milkweed of the Southwest and southern Rockies: thin, wiry, colony-forming, and the species behind most milkweed poisoning cases in the region. Ecologically useful on wild ground, but not a plant to introduce deliberately. Source: https://milkweedusa.com/species/poison-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary The whorled milkweed of the Southwest and southern Rockies: thin, wiry, colony-forming, and the species behind most milkweed poisoning cases in the region. Ecologically useful on wild ground, but not a plant to introduce deliberately. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias subverticillata (A. Gray) Vail | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Poison Milkweed, Western Whorled Milkweed, Horsetail Milkweed | | Status | Native | | Height | 1 ft–3 ft | | Spread | 2 ft–8 ft | | Flower color | white, green | | Bloom period | June to September | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 4-9 | | Leaf arrangement | whorled | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, Colorado, Kansas, Nebraska, New Mexico, Nevada, Oklahoma, Texas, Utah, Wyoming | ## Identification - Very narrow leaves in whorls, with smaller leaves clustered in the axils giving a bushy, feathery look. - Forms extensive rhizomatous colonies in disturbed sandy ground, roadsides and overgrazed pasture. - Small greenish-white flowers in clusters along the upper stem. ## Ecology Monarchs and queens do use it, and in the arid Southwest it is often the most abundant milkweed available. Its dense colonies support numerous milkweed specialists including large and small milkweed bugs and milkweed tussock moths. ## Growing Not recommended for planting. It colonizes aggressively, is difficult to remove, and creates a genuine hazard where horses or livestock are kept. ## Cautions The most dangerous milkweed for livestock in the western United States. Poisoning of horses, cattle and sheep is well documented, most often through baled hay. Do not plant near paddocks or hay meadows. ## Questions **Is poison milkweed dangerous to horses?** Yes. Asclepias subverticillata is highly toxic to horses, and because it dries without losing potency, contaminated hay is the usual route. Symptoms include tremors, staggering and cardiac arrhythmia. Remove it from hay ground and call a vet immediately if you suspect ingestion. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21298-2 - GBIF: https://www.gbif.org/species/3170284 - iNaturalist: https://www.inaturalist.org/taxa/127159 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_subverticillata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20subverticillata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20subverticillata ## Photographs - Asclepias subverticillata (SALLY KING, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_subverticillata.jpg - Asclepias subverticillata kz02 (Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_subverticillata_kz02.jpg - Asclepias subverticillata kz01 (Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_subverticillata_kz01.jpg - Asclepias subverticillata kz03 (Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_subverticillata_kz03.jpg - Asclepias subverticillata kz05 (Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_subverticillata_kz05.jpg - Asclepias subverticillata kz04 (Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_subverticillata_kz04.jpg - Asclepias subverticillata kz06 (Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_subverticillata_kz06.jpg - Asclepias subverticillata kz07 (Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_subverticillata_kz07.jpg ## How to cite Milkweed USA. (2026). Poison Milkweed (Asclepias subverticillata). https://milkweedusa.com/species/poison-milkweed/ --- # Poke Milkweed (Asclepias exaltata) > The woodland milkweed. Tall and slender with broad thin leaves like pokeweed, carrying loose, drooping clusters of green-and-white flowers that hang like small chandeliers along a shaded forest edge. Source: https://milkweedusa.com/species/poke-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary The woodland milkweed. Tall and slender with broad thin leaves like pokeweed, carrying loose, drooping clusters of green-and-white flowers that hang like small chandeliers along a shaded forest edge. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias exaltata L. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Poke Milkweed, Tall Milkweed | | Status | Native | | Height | 3 ft–6 ft | | Spread | 1.5 ft–2.5 ft | | Flower color | white, green | | Bloom period | June to July | | Light | Part shade, Shade | | Soil moisture | Average | | USDA zones | 3-8 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 3 | | US states recorded | Alabama, Connecticut, District of Columbia, Delaware, Georgia, Iowa, Illinois, Indiana, Kentucky, Massachusetts, Maryland, Maine, Michigan, Minnesota, North Carolina, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, Vermont, Wisconsin, West Virginia | ## Identification - Grows in shade and dappled woodland, which no other milkweed reliably does. - Flower clusters are loose and pendulous, with widely spaced flowers on long stalks. - Petals green-tinged white, reflexed sharply back from pure white hoods. - Leaves broad, thin, pointed at both ends, on distinct stalks. ## Ecology The only significant monarch host in eastern woodland habitats, and it hybridises occasionally with common milkweed where the two meet in clearings. ## Growing Genuinely useful for shady gardens. Give it part shade, humus-rich moist soil and, if possible, no competition from tree roots. Well behaved and clump-forming. ## Cautions Standard milkweed cautions. ## Questions **Is there a milkweed that grows in shade?** Poke milkweed (A. exaltata) is the one. It grows at woodland edges and in dappled shade across the eastern states. Fourleaf milkweed (A. quadrifolia) is a smaller second option for dry woodland. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94266-1 - GBIF: https://www.gbif.org/species/3170307 - iNaturalist: https://www.inaturalist.org/taxa/125386 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_exaltata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20exaltata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20exaltata ## Photographs - Asclepias exaltata flower (Dcharris555, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_exaltata_flower.jpg - Asclepias exaltata (2985661678) (homeredwardprice, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_exaltata_(2985661678).jpg - Asclepias exaltata (4804174527) (peganum, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_exaltata_(4804174527).jpg - Asclepias exaltata (4804173691) (peganum, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_exaltata_(4804173691).jpg - Asclepias exaltata (4804165729) (peganum, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_exaltata_(4804165729).jpg - Asclepias exaltata (7487165508) (peganum, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_exaltata_(7487165508).jpg - Asclepias exaltata (7487169598) (peganum, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_exaltata_(7487169598).jpg - Asclepias exaltata (7487167116) (peganum, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_exaltata_(7487167116).jpg ## How to cite Milkweed USA. (2026). Poke Milkweed (Asclepias exaltata). https://milkweedusa.com/species/poke-milkweed/ --- # Prairie Milkweed (Asclepias sullivantii) > Common milkweed’s refined cousin: the same big pink umbels and broad leaves, but smooth and hairless throughout, with an elegant red midrib and none of the coarseness. A tallgrass prairie plant that has declined sharply with the prairie itself. Source: https://milkweedusa.com/species/prairie-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary Common milkweed’s refined cousin: the same big pink umbels and broad leaves, but smooth and hairless throughout, with an elegant red midrib and none of the coarseness. A tallgrass prairie plant that has declined sharply with the prairie itself. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias sullivantii Engelm. ex A. Gray | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Prairie Milkweed, Sullivant’s Milkweed, Smooth Milkweed | | Status | Native | | Height | 2 ft–4 ft | | Spread | 1.5 ft–3 ft | | Flower color | pink, rose | | Bloom period | June to July | | Light | Full sun | | Soil moisture | Average, Wet | | USDA zones | 3-7 | | Leaf arrangement | opposite | | Leaf shape | oblong | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 5 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 4 | | US states recorded | Iowa, Illinois, Indiana, Kansas, Kentucky, Michigan, Minnesota, Missouri, North Dakota, Nebraska, Ohio, Oklahoma, South Dakota, Wisconsin | ## Identification - Completely smooth and hairless, with no down on stems, leaves or pods. - Leaf midrib is often flushed pink or red. - Leaves have a small abrupt point at the tip and are held stiffly upright. - Pods are smooth with only a few short blunt projections, unlike the warty pods of common milkweed. ## Ecology A high-value monarch host with broad, soft leaves, now uncommon because it grows on exactly the deep moist prairie soils that were converted to row crops. Conservation-listed in several states. ## Growing A far better garden plant than common milkweed: similar looks, much slower spread. Prefers heavier, moister soil. Seed and plants are increasingly available from prairie nurseries. ## Cautions Standard milkweed cautions. ## Questions **How is prairie milkweed different from common milkweed?** Prairie milkweed is completely hairless, has a reddish leaf midrib and nearly smooth pods, and spreads far less aggressively. Common milkweed is downy throughout with warty, spiny pods. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94678-1 - GBIF: https://www.gbif.org/species/3170265 - iNaturalist: https://www.inaturalist.org/taxa/158761 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_sullivantii - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20sullivantii.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20sullivantii ## Photographs - Asclepias sullivantii (gmayfield10, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_sullivantii.jpg - Prairie Milkweed (Asclepias sullivantii) - 28366153785 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Prairie_Milkweed_(Asclepias_sullivantii)_-_28366153785.jpg - Prairie Milkweed (Asclepias sullivantii) - 28262579022 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Prairie_Milkweed_(Asclepias_sullivantii)_-_28262579022.jpg - Prairie Milkweed (Asclepias sullivantii) (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Prairie_Milkweed_(Asclepias_sullivantii).jpg - Prairie Milkweed (Asclepias sullivantii) - 28287343981 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Prairie_Milkweed_(Asclepias_sullivantii)_-_28287343981.jpg - Prairie Milkweed (Asclepias sullivantii) - 28366208795 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Prairie_Milkweed_(Asclepias_sullivantii)_-_28366208795.jpg - Prairie Milkweed (Asclepias sullivantii) - 28262660652 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Prairie_Milkweed_(Asclepias_sullivantii)_-_28262660652.jpg - Prairie Milkweed (Asclepias sullivantii) - 28083645100 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Prairie_Milkweed_(Asclepias_sullivantii)_-_28083645100.jpg ## How to cite Milkweed USA. (2026). Prairie Milkweed (Asclepias sullivantii). https://milkweedusa.com/species/prairie-milkweed/ --- # Prostrate Milkweed (Asclepias prostrata) > A federally endangered milkweed known from a few sites in the south Texas brush country, growing completely flat against gravelly ground with small greenish-white flowers. It was listed under the Endangered Species Act in 2023. Source: https://milkweedusa.com/species/prostrate-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A federally endangered milkweed known from a few sites in the south Texas brush country, growing completely flat against gravelly ground with small greenish-white flowers. It was listed under the Endangered Species Act in 2023. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias prostrata W.H. Blackwell | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Prostrate Milkweed | | Status | Native; rare or legally protected in part of its range | | Height | 2 in–6 in | | Spread | 8 in–1.7 ft | | Flower color | green, white | | Bloom period | March to September | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 8-10 | | Leaf arrangement | opposite | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Texas | ## Identification - Entirely prostrate, with stems lying flat on bare gravelly soil. - Small narrow opposite leaves and tiny greenish-white flowers. - Known only from Starr and Zapata counties in south Texas and adjacent Mexico. ## Ecology Threatened by brush clearing, energy development and border infrastructure. Most surviving populations are tiny. ## Growing Federally endangered. Collection is prohibited; report sightings to Texas Parks and Wildlife. ## Cautions Listed as Endangered under the US Endangered Species Act. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21269-2 - GBIF: https://www.gbif.org/species/3170330 - iNaturalist: https://www.inaturalist.org/taxa/158755 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_prostrata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20prostrata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20prostrata ## Photographs - Asclepias prostrata in habitat (Sam Kieschnick, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_prostrata_in_habitat.jpg - Closeup of Asclepias prostrata in flower (Sam Kieschnick, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Closeup_of_Asclepias_prostrata_in_flower.jpg - Prostrate Milkweed photographed in Texas, US (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/71035195 - Prostrate Milkweed photographed in Texas, US (Eric Knight, CC BY 4.0): https://www.inaturalist.org/observations/44713620 - Prostrate Milkweed photographed in Texas, US (Reid Hardin, CC BY 4.0): https://www.inaturalist.org/observations/85386280 - Prostrate Milkweed photographed in Texas, US (Turner Brockman, CC BY-SA 4.0): https://www.inaturalist.org/observations/304856514 - Prostrate Milkweed photographed in Texas, US (Joseph Aubert, CC BY 4.0): https://www.inaturalist.org/observations/232205838 - Prostrate Milkweed photographed in Texas, US (Michelle W. （鍾偉瑋）, CC BY 4.0): https://www.inaturalist.org/observations/123192027 ## How to cite Milkweed USA. (2026). Prostrate Milkweed (Asclepias prostrata). https://milkweedusa.com/species/prostrate-milkweed/ --- # Purple Milkweed (Asclepias purpurascens) > The most intensely colored milkweed in eastern North America, with deep magenta-purple flower heads held upright above broad leaves, blooming a few weeks before common milkweed. Uncommon and declining nearly everywhere, and worth every effort to establish. Source: https://milkweedusa.com/species/purple-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary The most intensely colored milkweed in eastern North America, with deep magenta-purple flower heads held upright above broad leaves, blooming a few weeks before common milkweed. Uncommon and declining nearly everywhere, and worth every effort to establish. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias purpurascens L. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Purple Milkweed | | Status | Native | | Height | 2 ft–4 ft | | Spread | 1.5 ft–2.5 ft | | Flower color | purple, magenta | | Bloom period | May to July | | Light | Full sun, Part shade | | Soil moisture | Average, Dry | | USDA zones | 3-8 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 5 | | Nectar value (0-5) | 4 | | US states recorded | Alabama, Arkansas, Connecticut, District of Columbia, Delaware, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Mississippi, North Carolina, Nebraska, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Virginia, Vermont, Wisconsin, West Virginia | ## Identification - Flowers are a saturated purple-magenta, far darker than the dusty pink of common milkweed. - Clusters are held erect at the top of the stem, not drooping. - Blooms noticeably earlier than common milkweed. - Leaves broad with a short abrupt tip, downy underneath. ## Ecology A species of woodland edges, savannas and open thickets, declining because fire suppression has closed those habitats. Listed as rare, threatened or endangered in more than a dozen states. ## Growing Excellent in a garden: upright, non-running and spectacular in flower. Tolerates part shade. Slow from seed and slow to establish; give it three years before judging it. ## Cautions Standard milkweed cautions. Never dig plants from the wild. ## Questions **What is the prettiest milkweed?** Purple milkweed (A. purpurascens) gets most votes for flower color, a deep magenta unmatched in the genus, with showy milkweed and butterfly weed close behind. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94577-1 - GBIF: https://www.gbif.org/species/3170271 - iNaturalist: https://www.inaturalist.org/taxa/125380 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_purpurascens - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20purpurascens.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20purpurascens ## Photographs - Asclepias purpurascens1 (Kurt Stüber [1], CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_purpurascens1.jpg - Asclepias purpurascens - Flickr - peganum (peganum from Small Dole, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_purpurascens_-_Flickr_-_peganum.jpg - Asclepias purpurascens - Flickr - FritzFlohrReynolds (Fritz Flohr Reynolds from USA, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_purpurascens_-_Flickr_-_FritzFlohrReynolds.jpg - Purple milkweed flowers (Steepcone at English Wikipedia, Public domain): https://commons.wikimedia.org/wiki/File:Purple_milkweed_flowers.jpg - Flower -Milkweed 095 (Chris Light, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Flower_-Milkweed_095.jpg - Asclepias cf. purpurascens (9344316398) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_cf._purpurascens_(9344316398).jpg - Asclepias cf. purpurascens (9344334762) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_cf._purpurascens_(9344334762).jpg - Asclepias cf. purpurascens (9344315350) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_cf._purpurascens_(9344315350).jpg ## How to cite Milkweed USA. (2026). Purple Milkweed (Asclepias purpurascens). https://milkweedusa.com/species/purple-milkweed/ --- # Red Milkweed (Asclepias rubra) > A rare bog and seepage-slope milkweed with dusky rose-red flowers and stiff, sharply pointed leaves, scattered thinly down the Atlantic coastal plain and listed as endangered in most northern states where it survives. Source: https://milkweedusa.com/species/red-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A rare bog and seepage-slope milkweed with dusky rose-red flowers and stiff, sharply pointed leaves, scattered thinly down the Atlantic coastal plain and listed as endangered in most northern states where it survives. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias rubra L. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Red Milkweed, Bog Milkweed | | Status | Native | | Height | 2 ft–4 ft | | Spread | 1 ft–1.7 ft | | Flower color | red, pink | | Bloom period | June to July | | Light | Full sun, Part shade | | Soil moisture | Wet | | USDA zones | 6-9 | | Leaf arrangement | opposite | | Leaf shape | lanceolate | | Sap | Milky latex | | Root system | Fibrous, clump-forming and easy to move | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Alabama, Connecticut, Delaware, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, New Jersey, New York, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia | ## Identification - Flowers dull red to rose, in one or a few upright clusters. - Leaves lance-shaped with a long tapering point and rounded base, held stiffly. - Acid bogs, seepage slopes and pitcher plant savannas. ## Ecology Highly habitat-restricted; declining wherever coastal plain wetlands are drained. ## Growing Difficult, needing acidic, permanently moist, low-nutrient conditions. ## Cautions Rare and legally protected in several states. Never collect from the wild. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94615-1 - GBIF: https://www.gbif.org/species/3170334 - iNaturalist: https://www.inaturalist.org/taxa/143553 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_rubra - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20rubra.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20rubra ## Photographs - Asclepias rubra (below) & cf. purpurascens (9341535131) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_rubra_(below)_%26_cf._purpurascens_(9341535131).jpg - Asclepias rubra (below) & cf. purpurascens (9341533749) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_rubra_(below)_%26_cf._purpurascens_(9341533749).jpg - Asclepias rubra (9341546893) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_rubra_(9341546893).jpg - Asclepias rubra (9341530955) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_rubra_(9341530955).jpg - Asclepias rubra (9341532801) (peganum from Henfield, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_rubra_(9341532801).jpg - Asclepias rubra (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_rubra.jpg - Asclepias rubra - 51308144212 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_rubra_-_51308144212.jpg - Asclepias rubra - 51308140137 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_rubra_-_51308140137.jpg ## How to cite Milkweed USA. (2026). Red Milkweed (Asclepias rubra). https://milkweedusa.com/species/red-milkweed/ --- # Rusby’s Milkweed (Asclepias rusbyi) > A slender milkweed of Arizona and New Mexico pine-oak woodland and mountain grassland, with narrow alternate leaves and small greenish-white flower clusters. It follows the summer monsoon rather than the spring. Source: https://milkweedusa.com/species/rusbys-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A slender milkweed of Arizona and New Mexico pine-oak woodland and mountain grassland, with narrow alternate leaves and small greenish-white flower clusters. It follows the summer monsoon rather than the spring. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias rusbyi (Vail) Woodson | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Rusby’s Milkweed | | Status | Native | | Height | 1 ft–2.5 ft | | Spread | 10 in–1.7 ft | | Flower color | green, white | | Bloom period | May to August | | Light | Full sun, Part shade | | Soil moisture | Dry | | USDA zones | 5-9 | | Leaf arrangement | alternate | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 2 | | US states recorded | Arizona, New Mexico | ## Identification - Narrow, alternate, often slightly folded leaves on a wiry upright stem. - Small greenish-white flowers in loose clusters. - Ponderosa pine and pine-oak woodland openings above about 5,000 feet. ## Ecology A mid-elevation host for monarchs and queens moving through the Arizona sky islands during the monsoon. ## Growing Not in general cultivation. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21285-2 - GBIF: https://www.gbif.org/species/3170311 - iNaturalist: https://www.inaturalist.org/taxa/158758 - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20rusbyi.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20rusbyi ## Photographs - Rusby’s Milkweed photographed in Canyonlands National Park, San Juan County, US-UT, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/54814011 - Rusby’s Milkweed photographed in Sonoita, AZ 85637, USA (Sue Carnahan, CC BY 4.0): https://www.inaturalist.org/observations/248605717 - Rusby’s Milkweed photographed in 86401, Kingman, AZ, US (CK2AZ, CC BY 4.0): https://www.inaturalist.org/observations/7520868 - Rusby’s Milkweed photographed in Catron County, NM, USA (Wendy McCrady, CC BY 4.0): https://www.inaturalist.org/observations/122021962 - Rusby’s Milkweed photographed in Coconino National Forest, Flagstaff, AZ, US (mark-groeneveld, CC BY 4.0): https://www.inaturalist.org/observations/125096803 - Rusby’s Milkweed photographed in Grant County, US-NM, US (Andrew Tree, CC BY 4.0): https://www.inaturalist.org/observations/239817608 - Rusby’s Milkweed photographed in Lincoln, Nevada, United States (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/56201466 ## How to cite Milkweed USA. (2026). Rusby’s Milkweed (Asclepias rusbyi). https://milkweedusa.com/species/rusbys-milkweed/ --- # Rush Milkweed (Asclepias subulata) > A leafless-looking fountain of blue-green pencil-thick stems topped with cream flowers, growing in the hottest, driest washes of the Sonoran and Mojave deserts. It looks like a sculpture and needs no water at all. Source: https://milkweedusa.com/species/rush-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A leafless-looking fountain of blue-green pencil-thick stems topped with cream flowers, growing in the hottest, driest washes of the Sonoran and Mojave deserts. It looks like a sculpture and needs no water at all. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias subulata Decne. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Rush Milkweed, Desert Milkweed, Ajamete | | Status | Native | | Height | 2 ft–6 ft | | Spread | 2 ft–4 ft | | Flower color | cream, white | | Bloom period | nearly year-round in frost-free areas | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 8-11 | | Leaf arrangement | opposite | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, California, Nevada, Utah | ## Identification - Effectively leafless, because the narrow leaves drop early and leave bundles of erect stems. - Stems pale blue-green, rush-like, growing in a dense vase-shaped clump. - Cream to white flowers in small clusters near the stem tips, almost year-round. ## Ecology A critical desert host and nectar source that remains available when everything else has dried up, supporting monarchs, queens and desert pollinators through the long dry season. ## Growing A superb xeriscape plant for Phoenix, Tucson, Palm Springs and Las Vegas gardens. Full sun, no supplemental water once established, no frost below about 20°F. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94672-1 - GBIF: https://www.gbif.org/species/3170301 - iNaturalist: https://www.inaturalist.org/taxa/62291 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_subulata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20subulata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20subulata ## Photographs - Asclepias subulata flowers (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_subulata_flowers.jpg - Asclepias subulata flowers 2 (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_subulata_flowers_2.jpg - Asclepias subulata (Stan Shebs, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_subulata.jpg - Rush Milkweed photographed in Arroyo Nacapule, Guaymas Municipality, Sonora, Mexico (Sue Carnahan, CC BY 4.0): https://www.inaturalist.org/observations/192961841 - Rush Milkweed photographed in San Bernardino County, CA, USA (Public domain (CC0), CC0): https://www.inaturalist.org/observations/195190895 - Rush Milkweed photographed in Los Cabos, Baja California Sur, Mexico (Bill Levine, CC BY 4.0): https://www.inaturalist.org/observations/18600029 - Rush Milkweed photographed in Clark County, NV, USA (Dominic Gentilcore, CC BY 4.0): https://www.inaturalist.org/observations/50518000 - Rush Milkweed photographed in La Paz, B.C.S., México (Daniela Gámez, CC BY 4.0): https://www.inaturalist.org/observations/34852553 ## How to cite Milkweed USA. (2026). Rush Milkweed (Asclepias subulata). https://milkweedusa.com/species/rush-milkweed/ --- # Ruth’s Milkweed (Asclepias ruthiae) > A low, spreading Colorado Plateau milkweed of red sand and slickrock country, with small thick leaves and pale pink-cream flowers held close to the ground among the sandstone. Source: https://milkweedusa.com/species/ruths-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A low, spreading Colorado Plateau milkweed of red sand and slickrock country, with small thick leaves and pale pink-cream flowers held close to the ground among the sandstone. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias ruthiae Maguire | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Ruth’s Milkweed | | Status | Native | | Height | 4 in–1 ft | | Spread | 10 in–2 ft | | Flower color | pink, cream | | Bloom period | April to June | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 5-9 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 60 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Arizona, Nevada, Utah | ## Identification - Prostrate to low-spreading stems radiating from a central taproot. - Small, thick, blunt leaves, often folded and gray-tinged. - Pale pink to cream flowers in small clusters near the stem tips. ## Ecology A sandy-soil specialist of the Colorado Plateau, used by monarchs and queens moving through canyon country in spring. ## Growing Rarely available. Needs pure sand, full exposure and no summer irrigation. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21286-2 - GBIF: https://www.gbif.org/species/3574177 - iNaturalist: https://www.inaturalist.org/taxa/898625 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_ruthiae - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20ruthiae.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20ruthiae ## Photographs - Asclepias ruthiae in flower (Brad Grimm, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_ruthiae_in_flower.jpg - Asclepias uncialis subsp. ruthiae kz02 (Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_uncialis_subsp._ruthiae_kz02.jpg - Asclepias uncialis subsp. ruthiae kz01 (Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_uncialis_subsp._ruthiae_kz01.jpg - Ruth’s Milkweed photographed in Emery County, US-UT, US (Parker James Lloyd, CC BY 4.0): https://www.inaturalist.org/observations/349158179 - Ruth’s Milkweed photographed in Utah, US (Kenzie Anderson-Bell, CC BY 4.0): https://www.inaturalist.org/observations/280644260 - Ruth’s Milkweed photographed in Emery, Utah, United States (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/160688515 - Ruth’s Milkweed photographed in Wayne County, US-UT, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/216446370 - Ruth’s Milkweed photographed in Huntington, UT, US (Dee Shea Himes, CC BY 4.0): https://www.inaturalist.org/observations/215572578 ## How to cite Milkweed USA. (2026). Ruth’s Milkweed (Asclepias ruthiae). https://milkweedusa.com/species/ruths-milkweed/ --- # Sand Milkweed (Asclepias arenaria) > A stout, velvety-gray milkweed of deep sand, found in sandhills, blowouts and dune country from Nebraska to Texas, with crowded cream flower clusters and thick wavy-edged leaves. Source: https://milkweedusa.com/species/sand-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A stout, velvety-gray milkweed of deep sand, found in sandhills, blowouts and dune country from Nebraska to Texas, with crowded cream flower clusters and thick wavy-edged leaves. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias arenaria Torr. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Sand Milkweed, Western Sand Milkweed | | Status | Native | | Height | 1 ft–2.5 ft | | Spread | 1 ft–3 ft | | Flower color | cream, green | | Bloom period | June to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 4-8 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas, Utah | ## Identification - Whole plant densely covered in short white hairs, giving a gray cast. - Leaves thick with distinctly wavy margins, held stiffly. - Grows only in deep, loose sand, so habitat alone nearly identifies it. ## Ecology An important monarch host in the Nebraska Sandhills and southern plains dune systems, where its broad leaves are a rare resource. ## Growing Requires pure sand and sharp drainage; unsuited to ordinary garden soil. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94112-1 - GBIF: https://www.gbif.org/species/3170290 - iNaturalist: https://www.inaturalist.org/taxa/158732 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_arenaria - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20arenaria.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20arenaria ## Photographs - Asclepias arenaria - 51295254293 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_arenaria_-_51295254293.jpg - Asclepias arenaria (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_arenaria.jpg - Asclepias arenaria - 51295099771 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_arenaria_-_51295099771.jpg - Asclepias arenaria - 51295263658 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_arenaria_-_51295263658.jpg - Asclepias arenaria - 51295266073 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_arenaria_-_51295266073.jpg - Asclepias arenaria - 51295800229 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_arenaria_-_51295800229.jpg - Asclepias arenaria - 51296082445 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_arenaria_-_51296082445.jpg - Asclepias arenaria - pollinarium on petal (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_arenaria_-_pollinarium_on_petal.jpg ## How to cite Milkweed USA. (2026). Sand Milkweed (Asclepias arenaria). https://milkweedusa.com/species/sand-milkweed/ --- # Savannah Milkweed (Asclepias pedicellata) > A small, easily overlooked coastal plain milkweed with narrow leaves and a few pale greenish-yellow flowers on long stalks, growing in damp pine savanna and flatwoods. Source: https://milkweedusa.com/species/savannah-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A small, easily overlooked coastal plain milkweed with narrow leaves and a few pale greenish-yellow flowers on long stalks, growing in damp pine savanna and flatwoods. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias pedicellata Walter | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Savannah Milkweed, Stalked Milkweed | | Status | Native | | Height | 6 in–1.5 ft | | Spread | 6 in–1 ft | | Flower color | yellow, green | | Bloom period | April to September | | Light | Full sun | | Soil moisture | Wet, Average | | USDA zones | 8-10 | | Leaf arrangement | opposite | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | None required | | Monarch value (0-5) | 2 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 2 | | US states recorded | Florida, Georgia | ## Identification - Very few flowers per plant, each on a conspicuously long stalk. - Pale greenish-yellow flowers, unusual in the genus. - Damp pine savanna and flatwoods on the coastal plain. ## Ecology A fire-dependent flatwoods species that disappears where burning ceases. ## Growing Rarely cultivated. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94531-1 - GBIF: https://www.gbif.org/species/3170245 - iNaturalist: https://www.inaturalist.org/taxa/158754 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_pedicellata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20pedicellata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20pedicellata ## Photographs - Asclepias pedicellata 309963918 (Justin, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_pedicellata_309963918.jpg - Asclepias pedicellata 215561070 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_pedicellata_215561070.jpg - Asclepias pedicellata 215561092 (Alex Abair, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_pedicellata_215561092.jpg - Savannah Milkweed photographed in JUPITER INLET, FL 33469, USA (Michelle Sevcovas, CC BY 4.0): https://www.inaturalist.org/observations/45926372 - Savannah Milkweed photographed in Osceola County, US-FL, US (Valerie Anderson, CC BY 4.0): https://www.inaturalist.org/observations/249399201 - Savannah Milkweed photographed in Fred C. Babcock-Cecil M. Webb Wildlife Management Area, Charlotte County, US-FL, US (Jay Horn, CC BY 4.0): https://www.inaturalist.org/observations/21611708 - Savannah Milkweed photographed in Florida, US (Jason K., CC BY 4.0): https://www.inaturalist.org/observations/91073873 - Savannah Milkweed photographed in Ochlockonee Bay, FL 32346, USA (Briggs Armstrong, CC BY 4.0): https://www.inaturalist.org/observations/30206574 ## How to cite Milkweed USA. (2026). Savannah Milkweed (Asclepias pedicellata). https://milkweedusa.com/species/savannah-milkweed/ --- # Serpentine Milkweed (Asclepias solanoana) > A prostrate northern California endemic confined to serpentine barrens, forming flat mats of round gray-green leaves studded with small cream flowers. It grows on soil so metal-rich that almost nothing else survives. Source: https://milkweedusa.com/species/serpentine-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A prostrate northern California endemic confined to serpentine barrens, forming flat mats of round gray-green leaves studded with small cream flowers. It grows on soil so metal-rich that almost nothing else survives. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias solanoana Woodson | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Serpentine Milkweed, Solano Milkweed | | Status | Native; rare or legally protected in part of its range | | Height | 4 in–10 in | | Spread | 1 ft–2 ft | | Flower color | cream, pink | | Bloom period | May to July | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 7-9 | | Leaf arrangement | opposite | | Leaf shape | orbicular | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 60 days cold-moist | | Monarch value (0-5) | 1 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | California | ## Identification - Completely prostrate mats on bare serpentine rock and soil. - Round, thick, gray-green leaves pressed to the ground. - Small cream flowers with pinkish hoods. ## Ecology A serpentine-endemic rarity of high conservation value and very limited distribution. ## Growing Should not be collected or cultivated from wild material. ## Cautions Rare California endemic; leave undisturbed. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:290390-2 - GBIF: https://www.gbif.org/species/3170277 - iNaturalist: https://www.inaturalist.org/taxa/62293 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_solanoana - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20solanoana.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20solanoana ## Photographs - Asclepias solanoana (Shasta-Trinity National Forest USDA Forest Service., CC0): https://commons.wikimedia.org/wiki/File:Asclepias_solanoana.jpeg - Serpentine Milkweed photographed in California, US (Don Loarie, CC BY 4.0): https://www.inaturalist.org/observations/6474783 - Serpentine Milkweed photographed in Mendocino National Forest, US-CA, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/6726146 - Serpentine Milkweed photographed in Trinity County, US-CA, US (Dee Shea Himes, CC BY 4.0): https://www.inaturalist.org/observations/70509360 - Serpentine Milkweed photographed in California, US (Trevor Van Loon, CC BY 4.0): https://www.inaturalist.org/observations/219453414 - Serpentine Milkweed photographed in Sonoma County, US-CA, US (Roger Raiche, CC BY 4.0): https://www.inaturalist.org/observations/80324534 - Serpentine Milkweed photographed in Trinity County, US-CA, US (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/122385606 - Serpentine Milkweed photographed in California, US (Steve Matson, CC BY 4.0): https://www.inaturalist.org/observations/52876286 ## How to cite Milkweed USA. (2026). Serpentine Milkweed (Asclepias solanoana). https://milkweedusa.com/species/serpentine-milkweed/ --- # Showy Milkweed (Asclepias speciosa) > The West’s answer to common milkweed, and the single most important monarch host plant between the Great Plains and the Sierra Nevada. Its flowers are the showiest in the genus: star-shaped, rose-pink, with long pointed hoods that give each cluster a spiky, ornamental look. Gray-green velvety foliage sets it apart at fifty paces. Source: https://milkweedusa.com/species/showy-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary The West’s answer to common milkweed, and the single most important monarch host plant between the Great Plains and the Sierra Nevada. Its flowers are the showiest in the genus: star-shaped, rose-pink, with long pointed hoods that give each cluster a spiky, ornamental look. Gray-green velvety foliage sets it apart at fifty paces. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias speciosa Torr. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Showy Milkweed, Greek Milkweed, Creek Milkweed | | Status | Native | | Height | 2 ft–5 ft | | Spread | 2 ft–8 ft | | Flower color | pink, rose | | Bloom period | May to August | | Light | Full sun | | Soil moisture | Average, Dry | | USDA zones | 3-9 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 5 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 5 | | US states recorded | Arizona, California, Colorado, Iowa, Idaho, Kansas, Minnesota, Missouri, Montana, North Dakota, Nebraska, New Mexico, Nevada, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington, Wisconsin, Wyoming | ## Identification - Hoods are long, narrow and sharply pointed, giving the flower head a distinctly starry silhouette. This is the key difference from common milkweed. - Leaves are thick, gray-green and densely velvety-hairy on both sides. - Flower clusters are held upright to slightly nodding, not fully drooping. - Pods are woolly and covered in soft, blunt projections. ## Ecology Carries the bulk of western monarch breeding along irrigation ditches, riverbanks and roadsides from the Front Range to the Cascades. Bumble bees, digger bees and hummingbird moths work the flowers heavily. In much of the Intermountain West it is the only large-leaved milkweed available to a female monarch. ## Growing Far better behaved than common milkweed but still rhizomatous, so expect a slowly widening patch rather than a discrete clump. Tolerates alkaline soils, clay, drought and cold. It is the default milkweed for a Colorado, Montana, Idaho or Utah garden, and it looks good enough for a front border. ## Cautions Mildly toxic to grazing animals in quantity. Sap is a skin and eye irritant, so wash hands after cutting stems. ## Questions **Is showy milkweed good for a home garden?** Yes, with room. It is more ornamental and much less rampant than common milkweed, but it still spreads by rhizome. Give it a bed at least six feet across, or plan on pulling shoots. **How do I tell showy milkweed from common milkweed?** Look at the flower. Showy milkweed has long, tapering, sharply pointed hoods that make the cluster look starry; common milkweed’s hoods are short and rounded. Showy milkweed leaves are also greyer and more velvety. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94654-1 - GBIF: https://www.gbif.org/species/3170260 - iNaturalist: https://www.inaturalist.org/taxa/62292 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_speciosa - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20speciosa.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20speciosa ## Photographs - Asclepias speciosa showy milkweed plant (Dcrjsr, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_speciosa_showy_milkweed_plant.JPG - Asclepias speciosa at Seedskadee NWR (52262973263) (USFWS Mountain Prairie, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_speciosa_at_Seedskadee_NWR_(52262973263).jpg - Asclepias speciosa at Seedskadee NWR 90 (48714856017) (USFWS Mountain Prairie, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_speciosa_at_Seedskadee_NWR_90_(48714856017).jpg - Asclepias speciosa at Seedskadee NWR 94 (48714355833) (USFWS Mountain Prairie, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_speciosa_at_Seedskadee_NWR_94_(48714355833).jpg - Asclepias speciosa at Seedskadee NWR 95 (48714349013) (USFWS Mountain Prairie, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_speciosa_at_Seedskadee_NWR_95_(48714349013).jpg - Asclepias speciosa and western harvester ant at Seedskadee National Wildlife Refuge (48714249742) (USFWS Mountain Prairie, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_speciosa_and_western_harvester_ant_at_Seedskadee_National_Wildlife_Refuge_(48714249742).jpg - Asclepias speciosa1jakesmome (vicki watkins from USA, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_speciosa1jakesmome.jpg - Asclepias speciosa (5258351774) (Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_speciosa_(5258351774).jpg ## How to cite Milkweed USA. (2026). Showy Milkweed (Asclepias speciosa). https://milkweedusa.com/species/showy-milkweed/ --- # Slimleaf Milkweed (Asclepias stenophylla) > A tall wand of a plant with grass-fine leaves and creamy-green flowers clustered tight against the stem, scattered through unplowed tallgrass and mixed-grass prairie. Source: https://milkweedusa.com/species/slimleaf-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A tall wand of a plant with grass-fine leaves and creamy-green flowers clustered tight against the stem, scattered through unplowed tallgrass and mixed-grass prairie. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias stenophylla A. Gray | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Slimleaf Milkweed, Narrow-leaf Green Milkweed | | Status | Native | | Height | 1.5 ft–3.3 ft | | Spread | 10 in–1.5 ft | | Flower color | cream, green | | Bloom period | June to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 4-8 | | Leaf arrangement | alternate | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 3 | | US states recorded | Arkansas, Colorado, Iowa, Kansas, Louisiana, Missouri, Montana, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, Wyoming | ## Identification - Extremely narrow alternate leaves, sometimes eight inches long and only a few millimeters wide. - Flowers greenish-cream in small axillary clusters up the stem. - Reliable indicator of high-quality remnant prairie. ## Ecology A prairie-remnant specialist; its presence usually signals ground that has never been plowed. ## Growing Rarely available; needs lean prairie soil and patience. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94664-1 - GBIF: https://www.gbif.org/species/3170321 - iNaturalist: https://www.inaturalist.org/taxa/158760 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_stenophylla - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20stenophylla.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20stenophylla ## Photographs - Asclepias stenophylla 141042195 (Samuel A. Schmid, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_stenophylla_141042195.jpg - Slimleaf Milkweed photographed in Plymouth County, IA, USA (timharris, CC BY 4.0): https://www.inaturalist.org/observations/167765300 - Slimleaf Milkweed photographed in 66502, Manhattan, KS, US (Ryan Donnelly, CC BY 4.0): https://www.inaturalist.org/observations/28082061 - Slimleaf Milkweed photographed in Ashland, KS 66502, USA (Ethan Rose, CC BY 4.0): https://www.inaturalist.org/observations/233020874 - Slimleaf Milkweed photographed in 7146–7178 I-20 Service Rd, Aledo, TX, US (Sam Kieschnick, CC BY 4.0): https://www.inaturalist.org/observations/30655176 - Slimleaf Milkweed photographed in Osage, Oklahoma, United States (Emily Geest, CC BY 4.0): https://www.inaturalist.org/observations/71066498 - Slimleaf Milkweed photographed in Texas, US (CH Hemphill, CC BY 4.0): https://www.inaturalist.org/observations/220574960 - Slimleaf Milkweed photographed in Minnesota, US (Rose Zappa, CC BY 4.0): https://www.inaturalist.org/observations/102126234 ## How to cite Milkweed USA. (2026). Slimleaf Milkweed (Asclepias stenophylla). https://milkweedusa.com/species/slimleaf-milkweed/ --- # Slimpod Milkweed (Asclepias quinquedentata) > A slight, wiry milkweed of Arizona and New Mexico mountain woodland with very narrow leaves and small cream-green flowers, producing the exceptionally slim pods that give it its name. Source: https://milkweedusa.com/species/slimpod-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A slight, wiry milkweed of Arizona and New Mexico mountain woodland with very narrow leaves and small cream-green flowers, producing the exceptionally slim pods that give it its name. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias quinquedentata A. Gray | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Slimpod Milkweed, Fivetooth Milkweed | | Status | Native | | Height | 1 ft–2.5 ft | | Spread | 8 in–1.3 ft | | Flower color | cream, green | | Bloom period | July to September | | Light | Part shade, Full sun | | Soil moisture | Dry | | USDA zones | 6-9 | | Leaf arrangement | opposite | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Arizona, New Mexico | ## Identification - Very narrow opposite leaves on thin, often leaning stems. - Small cream to greenish flowers in sparse clusters. - Pods notably slender and pencil-thin. ## Ecology A minor but genuine monsoon-season host in southwestern mountain woodland. ## Growing Not in cultivation. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94582-1 - GBIF: https://www.gbif.org/species/3170234 - iNaturalist: https://www.inaturalist.org/taxa/158757 - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20quinquedentata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20quinquedentata ## Photographs - Slimpod Milkweed photographed in Grant County, NM, USA (Andrew Tree, CC BY 4.0): https://www.inaturalist.org/observations/127395201 - Slimpod Milkweed photographed in Sierra Vista Southeast, AZ, USA (Sue Carnahan, CC BY 4.0): https://www.inaturalist.org/observations/241158380 - Slimpod Milkweed photographed in San Simon, AZ 85632, USA (botanygirl, CC BY 4.0): https://www.inaturalist.org/observations/390398058 - Slimpod Milkweed photographed in Grant County, NM, USA (Andrew Tree, CC BY 4.0): https://www.inaturalist.org/observations/127395201 - Slimpod Milkweed photographed in Grant County, NM, USA (Andrew Tree, CC BY 4.0): https://www.inaturalist.org/observations/127395201 - Slimpod Milkweed photographed in Grant County, NM, USA (Andrew Tree, CC BY 4.0): https://www.inaturalist.org/observations/127395201 - Slimpod Milkweed photographed in Grant County, NM, USA (Andrew Tree, CC BY 4.0): https://www.inaturalist.org/observations/127395201 - Slimpod Milkweed photographed in Grant County, NM, USA (Andrew Tree, CC BY 4.0): https://www.inaturalist.org/observations/127395201 ## How to cite Milkweed USA. (2026). Slimpod Milkweed (Asclepias quinquedentata). https://milkweedusa.com/species/slimpod-milkweed/ --- # Southern Milkweed (Asclepias viridula) > A rare wet-savanna milkweed of the Florida panhandle and south Georgia, with narrow leaves and small greenish-white flowers, tracked as threatened across its small range. Source: https://milkweedusa.com/species/southern-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A rare wet-savanna milkweed of the Florida panhandle and south Georgia, with narrow leaves and small greenish-white flowers, tracked as threatened across its small range. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias viridula Chapm. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Southern Milkweed | | Status | Native; rare or legally protected in part of its range | | Height | 1 ft–2.5 ft | | Spread | 8 in–1.2 ft | | Flower color | green, white | | Bloom period | May to August | | Light | Full sun | | Soil moisture | Wet | | USDA zones | 8-9 | | Leaf arrangement | opposite | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Fibrous, clump-forming and easy to move | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Florida, Georgia | ## Identification - Slender upright stems in permanently damp pine savanna and bog edges. - Small greenish-white flowers in sparse clusters. - Restricted to the eastern Gulf coastal plain. ## Ecology Dependent on frequently burned wet savanna, a habitat reduced to fragments across the Gulf coastal plain. ## Growing Rare and state-tracked. Do not collect from the wild. ## Cautions Rare and legally tracked in Florida and Georgia. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94738-1 - GBIF: https://www.gbif.org/species/3170279 - iNaturalist: https://www.inaturalist.org/taxa/158764 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_viridula - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20viridula.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20viridula ## Photographs - Southern Milkweed photographed in Florida, US (Leyla, CC BY 4.0): https://www.inaturalist.org/observations/365210896 - Southern Milkweed photographed in Florida, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/311335349 - Southern Milkweed photographed in Bristol, FL 32321, USA (Scott Allen Davis, CC BY 4.0): https://www.inaturalist.org/observations/213068543 - Southern Milkweed photographed in Florida, US (Athena Philips, CC BY 4.0): https://www.inaturalist.org/observations/214451799 - Southern Milkweed photographed in Franklin County, FL, USA (Laura Gaudette, CC BY 4.0): https://www.inaturalist.org/observations/63669107 - Southern Milkweed photographed in Florida, US (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/92318852 - Southern Milkweed photographed in Florida, US (Scott Ward, CC BY 4.0): https://www.inaturalist.org/observations/77807036 ## How to cite Milkweed USA. (2026). Southern Milkweed (Asclepias viridula). https://milkweedusa.com/species/southern-milkweed/ --- # Sperry’s Milkweed (Asclepias sperryi) > A rare Trans-Pecos endemic of limestone ridges and rocky slopes in far west Texas, with thread-fine leaves and small cream flowers, known from very few localities. Source: https://milkweedusa.com/species/sperrys-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A rare Trans-Pecos endemic of limestone ridges and rocky slopes in far west Texas, with thread-fine leaves and small cream flowers, known from very few localities. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias sperryi Woodson | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Sperry’s Milkweed | | Status | Native; rare or legally protected in part of its range | | Height | 8 in–1.7 ft | | Spread | 8 in–1.5 ft | | Flower color | cream, green | | Bloom period | May to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 7-9 | | Leaf arrangement | opposite | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Texas | ## Identification - Thread-fine opposite leaves on slender clustered stems. - Small cream-green flowers in sparse terminal clusters. - Limestone slopes and ridges in the Trans-Pecos. ## Ecology A narrow Texas endemic with little documented ecology and a small known range. ## Growing Not in cultivation; leave wild plants undisturbed. ## Cautions A rare Texas endemic. Photograph and report rather than collect. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21294-2 - GBIF: https://www.gbif.org/species/3170239 - iNaturalist: https://www.inaturalist.org/taxa/158759 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_sperryi - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20sperryi.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20sperryi ## Photographs - Asclepias sperryi in flower (Richard Rintz, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_sperryi_in_flower.jpg ## How to cite Milkweed USA. (2026). Sperry’s Milkweed (Asclepias sperryi). https://milkweedusa.com/species/sperrys-milkweed/ --- # Swamp Milkweed (Asclepias incarnata) > The best-behaved milkweed there is: a tidy, clump-forming, non-running perennial with narrow willow-like leaves and domed clusters of vivid rose-pink flowers that smell faintly of cinnamon. It grows in wet ground in the wild but is perfectly happy in ordinary garden soil, which makes it the safest choice for a border. Source: https://milkweedusa.com/species/swamp-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary The best-behaved milkweed there is: a tidy, clump-forming, non-running perennial with narrow willow-like leaves and domed clusters of vivid rose-pink flowers that smell faintly of cinnamon. It grows in wet ground in the wild but is perfectly happy in ordinary garden soil, which makes it the safest choice for a border. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias incarnata L. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Swamp Milkweed, Rose Milkweed, Marsh Milkweed, Pink Milkweed | | Status | Native | | Height | 3 ft–5 ft | | Spread | 2 ft–3 ft | | Flower color | pink, rose, white | | Bloom period | June to September | | Light | Full sun, Part shade | | Soil moisture | Wet, Average | | USDA zones | 3-9 | | Leaf arrangement | opposite | | Leaf shape | lanceolate | | Sap | Milky latex | | Root system | Fibrous, clump-forming and easy to move | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 5 | | Garden value (0-5) | 5 | | Nectar value (0-5) | 5 | | US states recorded | Alabama, Arkansas, Colorado, Connecticut, District of Columbia, Delaware, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Mississippi, Montana, North Carolina, North Dakota, Nebraska, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Vermont, Wisconsin, West Virginia, Wyoming | ## Identification - Narrow, smooth, willow-like leaves on a slender stem that branches near the top. - Flowers are a much brighter, cleaner pink than common milkweed, in neat rounded clusters held upright. - Pods are slim, smooth and spindle-shaped, never warty. - Forms a discrete crown; it does not send up shoots away from the plant. ## Ecology Excellent monarch host and outstanding late-season nectar plant, blooming when common milkweed has finished. Great spangled fritillaries, tiger swallowtails and long-tongued bees dominate the flowers. Because it holds foliage late and stays soft, it often carries the last monarch generation of the year in the Midwest and Northeast. ## Growing The one to plant if you only plant one. It stays where you put it, tolerates clay, standing water and rain gardens, and takes ordinary garden watering without complaint. Slow to emerge in spring. Cut back in late winter. Divides easily, unlike its taprooted relatives. The white form ‘Ice Ballet’ and compact ‘Cinderella’ are widely sold. ## Cautions Low toxicity risk in gardens. Aphid magnet. Expect orange oleander aphids, and leave them for the ladybirds rather than spraying, which kills monarch eggs. ## Questions **Does swamp milkweed need a swamp?** No. It is adapted to wet ground but grows well in average garden soil with normal watering. It simply will not tolerate prolonged drought the way butterfly weed does. **Is swamp milkweed aggressive?** No. It is fibrous-rooted and clump-forming, the least aggressive of the widely grown milkweeds and the right choice for a mixed perennial border. **When does swamp milkweed bloom?** Mid to late summer, typically July into September, later than common and showy milkweed. That makes it valuable for the final monarch generation of the season. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94351-1 - GBIF: https://www.gbif.org/species/3170266 - iNaturalist: https://www.inaturalist.org/taxa/125381 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_incarnata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20incarnata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20incarnata ## Photographs - Asclepias incarnata 5-eheep (5097206759) (Superior National Forest, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_incarnata_5-eheep_(5097206759).jpg - Asclepias incarnata 4-eheep (5097804326) (Superior National Forest, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_incarnata_4-eheep_(5097804326).jpg - Asclepias incarnata 3-eheep (5097206621) (Superior National Forest, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_incarnata_3-eheep_(5097206621).jpg - Asclepias incarnata - Swamp Milkweed (Fritzflohrreynolds, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_incarnata_-_Swamp_Milkweed.jpg - Asclepias incarnata (20617060945) (peganum from Small Dole, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_incarnata_(20617060945).jpg - Asclepias incarnata - Flickr - peganum (peganum from Small Dole, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_incarnata_-_Flickr_-_peganum.jpg - Asclepias incarnata - Flickr - peganum (1) (peganum from Small Dole, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_incarnata_-_Flickr_-_peganum_(1).jpg - Asclepias incarnata - Flickr - peganum (2) (peganum from Small Dole, England, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_incarnata_-_Flickr_-_peganum_(2).jpg ## How to cite Milkweed USA. (2026). Swamp Milkweed (Asclepias incarnata). https://milkweedusa.com/species/swamp-milkweed/ --- # Tall Green Milkweed (Asclepias hirtella) > A stiff, upright tallgrass-prairie milkweed with crowded narrow leaves and dense round clusters of small greenish-white flowers, common on prairie remnants and railroad rights of way through the Midwest. Source: https://milkweedusa.com/species/tall-green-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A stiff, upright tallgrass-prairie milkweed with crowded narrow leaves and dense round clusters of small greenish-white flowers, common on prairie remnants and railroad rights of way through the Midwest. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias hirtella (Pennell) Woodson | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Tall Green Milkweed, Prairie Milkweed | | Status | Native | | Height | 2 ft–4 ft | | Spread | 10 in–1.5 ft | | Flower color | green, white | | Bloom period | June to August | | Light | Full sun | | Soil moisture | Dry, Average | | USDA zones | 4-8 | | Leaf arrangement | alternate | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 3 | | US states recorded | Alabama, Arkansas, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Missouri, Mississippi, Nebraska, Ohio, Oklahoma, Tennessee, Texas, Wisconsin | ## Identification - Numerous narrow alternate leaves crowded up a single rigid stem. - Tight, ball-like clusters of small green-white flowers in the leaf axils. - Indicator of remnant prairie and old cemetery prairies. ## Ecology Used by monarchs and by a wide range of small prairie bees and wasps. ## Growing Available from prairie seed suppliers; needs lean soil and full sun. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21200-2 - GBIF: https://www.gbif.org/species/3170338 - iNaturalist: https://www.inaturalist.org/taxa/127690 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_hirtella - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20hirtella.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20hirtella ## Photographs - Asclepias hirtella (Mason Brock (Masebrock), Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_hirtella.jpg - Asclepias hirtella arkansas (Eric Hunt, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_hirtella_arkansas.jpg - Tall Green Milkweed (Asclepias hirtella) - Flickr - wackybadger (Joshua Mayer from Madison, WI, USA, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Tall_Green_Milkweed_(Asclepias_hirtella)_-_Flickr_-_wackybadger.jpg - Tall Green Milkweed (Asclepias hirtella) - Flickr - wackybadger (1) (Joshua Mayer from Madison, WI, USA, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Tall_Green_Milkweed_(Asclepias_hirtella)_-_Flickr_-_wackybadger_(1).jpg - Tall Green Milkweed (Asclepias hirtella) - Flickr - wackybadger (2) (Joshua Mayer from Madison, WI, USA, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Tall_Green_Milkweed_(Asclepias_hirtella)_-_Flickr_-_wackybadger_(2).jpg - Tall Green Milkweed (Asclepias hirtella) (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Tall_Green_Milkweed_(Asclepias_hirtella).jpg - Tall Green Milkweed (Asclepias hirtella) - 14789079055 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Tall_Green_Milkweed_(Asclepias_hirtella)_-_14789079055.jpg - Tall Green Milkweed (Asclepias hirtella) - 14808925473 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Tall_Green_Milkweed_(Asclepias_hirtella)_-_14808925473.jpg ## How to cite Milkweed USA. (2026). Tall Green Milkweed (Asclepias hirtella). https://milkweedusa.com/species/tall-green-milkweed/ --- # Texas Milkweed (Asclepias texana) > A refined Edwards Plateau endemic with thin dark green leaves and clean white flower clusters, growing in limestone canyons and creek beds through the Texas Hill Country. Source: https://milkweedusa.com/species/texas-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A refined Edwards Plateau endemic with thin dark green leaves and clean white flower clusters, growing in limestone canyons and creek beds through the Texas Hill Country. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias texana A. Heller | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Texas Milkweed | | Status | Native | | Height | 1 ft–3 ft | | Spread | 1 ft–2 ft | | Flower color | white | | Bloom period | May to September | | Light | Part shade, Full sun | | Soil moisture | Dry, Average | | USDA zones | 7-9 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 3 | | US states recorded | New Mexico, Texas | ## Identification - Pure white flowers in neat rounded clusters. - Thin, dark green, pointed leaves on a slender branching stem. - Limestone canyons, seeps and rocky stream banks in central Texas. ## Ecology A localised but valuable summer host and nectar plant in Hill Country canyon habitats. ## Growing A good, well-mannered garden plant for central Texas, taking part shade and limestone soil. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21305-2 - GBIF: https://www.gbif.org/species/3170347 - iNaturalist: https://www.inaturalist.org/taxa/158762 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_texana - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20texana.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20texana ## Photographs - Asclepias texana (Mason Brock (Masebrock), Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_texana.jpg - Near Border Hill - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Near_Border_Hill_-_Flickr_-_aspidoscelis.jpg - Near Cañada Montosa - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Near_Ca%C3%B1ada_Montosa_-_Flickr_-_aspidoscelis.jpg - Texas Milkweed photographed in Travis County, US-TX, US (Michelle W. （鍾偉瑋）, CC BY 4.0): https://www.inaturalist.org/observations/87046123 - Texas Milkweed photographed in Austin, TX, USA (Eric Knight, CC BY 4.0): https://www.inaturalist.org/observations/28262647 - Texas Milkweed photographed in Lost Maples State Natural Area, Vanderpool, TX, US (Cody Stricker, CC BY 4.0): https://www.inaturalist.org/observations/53809135 - Texas Milkweed photographed in Burnet County, US-TX, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/360016402 - Texas Milkweed photographed in Boerne, TX 78006, USA (Craig Hensley, CC BY 4.0): https://www.inaturalist.org/observations/52172881 ## How to cite Milkweed USA. (2026). Texas Milkweed (Asclepias texana). https://milkweedusa.com/species/texas-milkweed/ --- # Tropical Milkweed (Asclepias curassavica) > The scarlet-and-gold milkweed sold in nearly every garden center. It is not native to the United States, it flowers relentlessly, and in frost-free regions that is exactly the problem: it disrupts monarch migration and builds up parasite loads. Beautiful plant, genuinely bad ecological actor south of the frost line. Source: https://milkweedusa.com/species/tropical-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary The scarlet-and-gold milkweed sold in nearly every garden center. It is not native to the United States, it flowers relentlessly, and in frost-free regions that is exactly the problem: it disrupts monarch migration and builds up parasite loads. Beautiful plant, genuinely bad ecological actor south of the frost line. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias curassavica L. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Tropical Milkweed, Bloodflower, Mexican Butterfly Weed, Scarlet Milkweed | | Status | Not native to the United States | | Height | 2 ft–4 ft | | Spread | 1.5 ft–2.5 ft | | Flower color | red, orange, yellow | | Bloom period | nearly year-round in frost-free areas | | Light | Full sun, Part shade | | Soil moisture | Average | | USDA zones | 8-11 | | Leaf arrangement | opposite | | Leaf shape | lanceolate | | Sap | Milky latex | | Root system | Fibrous, clump-forming and easy to move | | Seed stratification | None required | | Monarch value (0-5) | 2 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 4 | | US states recorded | Alabama, Arizona, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, North Carolina, South Carolina, Texas | ## Identification - Flowers are two-toned, a red or orange corolla with a bright yellow-orange crown, unlike any native species. - Blooms continuously rather than in a defined season. - Smooth, dark green lance-shaped leaves; slender upright stems; no basal woodiness in the first year. - Pods are narrow, smooth and upright. ## Ecology Monarchs will lay on it eagerly, but in the Gulf states, California and Florida it stays green all winter and encourages butterflies to break their migration and breed year-round. Those resident populations accumulate the protozoan parasite Ophryocystis elektroscirrha (OE), which shortens lifespans and deforms wings. Studies also show that cardenolide levels rise under heat, which may harm larvae. ## Growing Grown as an annual north of zone 8 it is harmless and useful. It germinates without stratification, blooms in twelve weeks from seed and dies at the first frost. In zones 9 to 11, either cut it to the ground each October through February or, better, replace it with a native species. ## Cautions Several US counties and native plant societies now discourage or restrict its sale. If you garden in Florida, the Gulf Coast, southern California, Arizona or Hawaii, please choose a native milkweed instead. ## Questions **Is tropical milkweed bad for monarchs?** In frost-free regions, yes. Because it does not die back it supports winter breeding, which raises OE parasite infection rates dramatically and can interrupt migration. In cold-winter regions where frost kills it each year, the evidence of harm is much weaker. **Should I cut back my tropical milkweed?** If you are in zone 9 or warmer, cut every plant to within six inches of the ground in October and keep it cut through February. That mimics the natural winter dieback and reduces parasite build-up. **What should I plant instead of tropical milkweed?** Match your region: swamp milkweed and butterfly weed almost anywhere, aquatic milkweed or pinewoods milkweed in Florida, zizotes and antelope horns in Texas, narrowleaf milkweed in California. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94213-1 - GBIF: https://www.gbif.org/species/3170241 - iNaturalist: https://www.inaturalist.org/taxa/75602 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_curassavica - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20curassavica.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20curassavica ## Photographs - Asclepias curassavica (bloodflower) 1 (26056089288) (James St. John, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_curassavica_(bloodflower)_1_(26056089288).jpg - Asclepias curassavica (bloodflower) 2 (39030330915) (James St. John, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_curassavica_(bloodflower)_2_(39030330915).jpg - Asclepias curassavica (BG Zurich)-01 (Guérin Nicolas (messages) 09:51, 25 September 2008 (UTC), CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_curassavica_(BG_Zurich)-01.JPG - Asclepias curassavica (BG Zurich)-02 (Guérin Nicolas (messages) 09:52, 25 September 2008 (UTC), CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_curassavica_(BG_Zurich)-02.JPG - Anartia amathea - Asclepias curassavica - Schmetterlinghaus Burggarten Wien 01 (Manfred Werner / Tsui, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Anartia_amathea_-_Asclepias_curassavica_-_Schmetterlinghaus_Burggarten_Wien_01.jpg - Asclepias curassavica (5461131441) (carrotmadman6 from Mauritius, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_curassavica_(5461131441).jpg - Asclepias curassavica (5461132859) (carrotmadman6 from Mauritius, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_curassavica_(5461132859).jpg - Asclepias curassavica (15932169749) (John Tann from Sydney, Australia, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_curassavica_(15932169749).jpg ## How to cite Milkweed USA. (2026). Tropical Milkweed (Asclepias curassavica). https://milkweedusa.com/species/tropical-milkweed/ --- # Tufted Milkweed (Asclepias nummularia) > One of the smallest milkweeds in North America, a low tuft of tiny round woolly leaves on rocky Arizona desert slopes, easy to walk past even in flower. Source: https://milkweedusa.com/species/tufted-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary One of the smallest milkweeds in North America, a low tuft of tiny round woolly leaves on rocky Arizona desert slopes, easy to walk past even in flower. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias nummularia Torr. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Tufted Milkweed, Roundleaf Milkweed | | Status | Native | | Height | 2 in–8 in | | Spread | 6 in–1.2 ft | | Flower color | cream, green | | Bloom period | April to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 7-10 | | Leaf arrangement | opposite | | Leaf shape | orbicular | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 1 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Arizona | ## Identification - Tiny, nearly circular, densely hairy leaves. - Whole plant usually under six inches tall. - Rocky slopes and desert grassland in central and southern Arizona. ## Ecology A poorly documented Sonoran Desert specialist of limited but real value to desert pollinators. ## Growing Not in cultivation. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94488-1 - GBIF: https://www.gbif.org/species/3170341 - iNaturalist: https://www.inaturalist.org/taxa/158751 - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20nummularia.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20nummularia ## Photographs - Tufted Milkweed photographed in Old CCC Trail, Fort Davis, TX 79734, USA (Alison Northup, CC BY 4.0): https://www.inaturalist.org/observations/21475553 - Tufted Milkweed photographed in Santa Cruz County, AZ, USA (Sue Carnahan, CC BY 4.0): https://www.inaturalist.org/observations/198672573 - Tufted Milkweed photographed in Brewster County, TX, USA (Public domain (CC0), CC0): https://www.inaturalist.org/observations/46385918 - Tufted Milkweed photographed in Cochise County, AZ, USA (Laura Gaudette, CC BY 4.0): https://www.inaturalist.org/observations/358728655 - Tufted Milkweed photographed in 34460 Dgo., México (Miriam Sanchez Loera, CC BY 4.0): https://www.inaturalist.org/observations/205736632 - Tufted Milkweed photographed in Fort Davis, TX 79734, USA (mattmsa, CC BY 4.0): https://www.inaturalist.org/observations/60958917 - Tufted Milkweed photographed in Zacatecas, Mexico (quirino, CC BY 4.0): https://www.inaturalist.org/observations/356173396 - Tufted Milkweed photographed in Finley Tank Rd, Elgin, AZ, US (Brad Grimm, CC BY 4.0): https://www.inaturalist.org/observations/30908463 ## How to cite Milkweed USA. (2026). Tufted Milkweed (Asclepias nummularia). https://milkweedusa.com/species/tufted-milkweed/ --- # Velvetleaf Milkweed (Asclepias tomentosa) > A softly furred, low-growing milkweed of southeastern coastal sandhills and scrub, with greenish-cream flowers and leaves felted enough to feel like suede. Source: https://milkweedusa.com/species/velvetleaf-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A softly furred, low-growing milkweed of southeastern coastal sandhills and scrub, with greenish-cream flowers and leaves felted enough to feel like suede. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias tomentosa Elliott | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Velvetleaf Milkweed, Tuba Milkweed | | Status | Native | | Height | 1 ft–2.5 ft | | Spread | 1 ft–2.5 ft | | Flower color | green, cream | | Bloom period | April to July | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 7-10 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 2 | | US states recorded | Alabama, Florida, Georgia, South Carolina | ## Identification - Whole plant densely velvety to the touch. - Sprawling to weakly upright stems in deep coastal sand. - Small greenish-white flowers with cream hoods. ## Ecology A scarce component of Florida scrub and coastal sandhill communities. ## Growing Rarely cultivated; requires pure sand. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94697-1 - GBIF: https://www.gbif.org/species/3170331 - iNaturalist: https://www.inaturalist.org/taxa/145567 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_tomentosa - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20tomentosa.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20tomentosa ## Photographs - Asclepias tomentosa (Florida Native Plant Society, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_tomentosa.jpg - Asclepias tomentosa - 51299352068 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_tomentosa_-_51299352068.jpg - Asclepias tomentosa (2021) (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_tomentosa_(2021).jpg - Asclepias tomentosa - 51300184590 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_tomentosa_-_51300184590.jpg - Asclepias tomentosa - 51300185880 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_tomentosa_-_51300185880.jpg - Asclepias tomentosa - 51300187120 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_tomentosa_-_51300187120.jpg - Asclepias tomentosa 1 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_tomentosa_1.jpg - Asclepias tomentosa - 53812508572 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_tomentosa_-_53812508572.jpg ## How to cite Milkweed USA. (2026). Velvetleaf Milkweed (Asclepias tomentosa). https://milkweedusa.com/species/velvetleaf-milkweed/ --- # Welsh’s Milkweed (Asclepias welshii) > A federally threatened dune endemic known from only a handful of active sand dune systems on the Utah–Arizona border, including the Coral Pink Sand Dunes. Thick woolly gray leaves and creamy flower clusters on plants that survive by growing up through shifting sand. Source: https://milkweedusa.com/species/welshs-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A federally threatened dune endemic known from only a handful of active sand dune systems on the Utah–Arizona border, including the Coral Pink Sand Dunes. Thick woolly gray leaves and creamy flower clusters on plants that survive by growing up through shifting sand. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias welshii N.H. Holmgren & P.K. Holmgren | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Welsh’s Milkweed | | Status | Native; rare or legally protected in part of its range | | Height | 1.5 ft–4 ft | | Spread | 2 ft–5 ft | | Flower color | cream, pink | | Bloom period | May to July | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 5-8 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 60 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, Utah | ## Identification - Broad, thick, densely white-woolly leaves in well-spaced opposite pairs. - Creamy-white flowers tinged pink, in dense terminal clusters. - Grows only in active, shifting sand dunes, so habitat alone identifies it. ## Ecology A dune specialist whose rhizomes let it re-emerge after burial by moving sand. Off-road vehicle traffic and dune stabilisation by invasive plants are the principal threats. ## Growing Legally protected. Do not collect seed, plants or cuttings, and do not attempt to cultivate it from wild material. ## Cautions Listed as Threatened under the US Endangered Species Act. Collection is prohibited. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21339-2 - GBIF: https://www.gbif.org/species/3170262 - iNaturalist: https://www.inaturalist.org/taxa/158765 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_welshii - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20welshii.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20welshii ## Photographs - Welsh milkweed (Asclepias welshii) Habitat (6307381392) (USFWS Mountain-Prairie, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Welsh_milkweed_(Asclepias_welshii)_Habitat_(6307381392).jpg - Welsh milkweed (Asclepias welshii) Habitat (6307382808) (USFWS Mountain-Prairie, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Welsh_milkweed_(Asclepias_welshii)_Habitat_(6307382808).jpg - Asclepias welshii (Daniela Roth, USFWS, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_welshii.jpg - Welsh’s Milkweed photographed in Coral Pink Sand Dunes State Park, Kanab, UT, US (Jared Shorma, CC BY 4.0): https://www.inaturalist.org/observations/241602907 - Welsh’s Milkweed photographed in Canyon Point, UT 84741, USA (Darrin Gobble, CC BY 4.0): https://www.inaturalist.org/observations/117232610 - Welsh’s Milkweed photographed in United States (Public domain (CC0), CC0): https://www.inaturalist.org/observations/137475358 - Welsh’s Milkweed photographed in Kane County, UT, USA (Anders Hastings, CC BY 4.0): https://www.inaturalist.org/observations/308347610 - Welsh’s Milkweed photographed in Coral Pink Sand Dunes Rd, Kanab, UT, US (Parker James Lloyd, CC BY 4.0): https://www.inaturalist.org/observations/363951195 ## How to cite Milkweed USA. (2026). Welsh’s Milkweed (Asclepias welshii). https://milkweedusa.com/species/welshs-milkweed/ --- # Wheel Milkweed (Asclepias uncialis) > One of the rarest and smallest milkweeds in North America, a two-inch-high scatter of maroon-tinged flowers on the shortgrass steppe, tracked as a species of concern in several states including Colorado. Source: https://milkweedusa.com/species/wheel-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary One of the rarest and smallest milkweeds in North America, a two-inch-high scatter of maroon-tinged flowers on the shortgrass steppe, tracked as a species of concern in several states including Colorado. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias uncialis Greene | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Wheel Milkweed, Dwarf Milkweed, Greene’s Milkweed | | Status | Native; rare or legally protected in part of its range | | Height | 2 in–6 in | | Spread | 4 in–1 ft | | Flower color | maroon, green | | Bloom period | April to June | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 4-8 | | Leaf arrangement | opposite | | Leaf shape | narrow | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 60 days cold-moist | | Monarch value (0-5) | 1 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Arizona, Colorado, Kansas, New Mexico, Nevada, Utah, Wyoming | ## Identification - Minute: frequently no taller than a golf tee, easily overlooked among grass. - Flowers dull maroon and green, held just above the soil. - Appears briefly in spring then disappears. ## Ecology Poorly understood. Habitat loss to cultivation and energy development is the principal threat; report sightings to your state natural heritage program. ## Growing Do not attempt to collect. This species should be left entirely alone in the wild. ## Cautions Rare and legally protected in parts of its range. Photograph, record and leave it. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94711-1 - GBIF: https://www.gbif.org/species/3170289 - iNaturalist: https://www.inaturalist.org/taxa/126674 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_uncialis - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20uncialis.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20uncialis ## Photographs - Asclepias uncialis lg (Steve Olson, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_uncialis_lg.jpg - Asclepias uncialis - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_uncialis_-_Flickr_-_aspidoscelis.jpg - Asclepias uncialis - Flickr - aspidoscelis (1) (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_uncialis_-_Flickr_-_aspidoscelis_(1).jpg - Wheel Milkweed photographed in 33.169 -108.748 (Public domain (CC0), CC0): https://www.inaturalist.org/observations/9259239 - Wheel Milkweed photographed in Grant County, US-NM, US (Andrew Tree, CC BY 4.0): https://www.inaturalist.org/observations/207193553 - Wheel Milkweed photographed in Placitas, NM 87043, USA (Eric Knight, CC BY 4.0): https://www.inaturalist.org/observations/212004205 ## How to cite Milkweed USA. (2026). Wheel Milkweed (Asclepias uncialis). https://milkweedusa.com/species/wheel-milkweed/ --- # White Milkweed (Asclepias variegata) > Tight snowball clusters of pure white flowers, each ringed with a fine purple-red band at its base, glowing in the half-shade of southeastern oak and pine woods. The most striking white-flowered milkweed in North America. Source: https://milkweedusa.com/species/white-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary Tight snowball clusters of pure white flowers, each ringed with a fine purple-red band at its base, glowing in the half-shade of southeastern oak and pine woods. The most striking white-flowered milkweed in North America. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias variegata L. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | White Milkweed, Redring Milkweed | | Status | Native | | Height | 1.5 ft–3.5 ft | | Spread | 1 ft–2 ft | | Flower color | white | | Bloom period | May to July | | Light | Part shade, Shade | | Soil moisture | Dry, Average | | USDA zones | 5-9 | | Leaf arrangement | opposite | | Leaf shape | ovate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 4 | | Nectar value (0-5) | 4 | | US states recorded | Alabama, Arkansas, Connecticut, District of Columbia, Delaware, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maryland, Missouri, Mississippi, North Carolina, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, West Virginia | ## Identification - Dense, almost spherical clusters of white flowers, unlike the loose heads of poke milkweed. - A distinct dark red or purple ring where the hoods meet the corolla. - Broad dark green leaves in well-spaced opposite pairs. - Woodland and woodland-edge habitat. ## Ecology An important nectar source for woodland butterflies and a modest monarch host in southeastern forests. ## Growing Beautiful and well behaved in a shaded native garden with good drainage. Slow from seed; scarce in the trade. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94717-1 - GBIF: https://www.gbif.org/species/3170272 - iNaturalist: https://www.inaturalist.org/taxa/127691 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_variegata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20variegata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20variegata ## Photographs - Asclepias variegata (Mason Brock (Masebrock), Public domain): https://commons.wikimedia.org/wiki/File:Asclepias_variegata.jpg - Asclepias variegata 2 (Eric Hunt, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_variegata_2.jpg - Asclepias variegata (2022) (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_variegata_(2022).jpg - Asclepias variegata - 52074145290 (sonnia hill, CC BY 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_variegata_-_52074145290.jpg - Scarab beetle on Redring Milkweed (James Leon Young, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Scarab_beetle_on_Redring_Milkweed.jpg - Milkweed Atlanta State Park Texas 2023 (Larry D. Moore, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Milkweed_Atlanta_State_Park_Texas_2023.jpg - White Milkweed photographed in Allegany County, US-MD, US (Tom Field, CC BY 4.0): https://www.inaturalist.org/observations/121521691 - White Milkweed photographed in Indian Point Trail (Daniel S. Katz, CC BY 4.0): https://www.inaturalist.org/observations/119510161 ## How to cite Milkweed USA. (2026). White Milkweed (Asclepias variegata). https://milkweedusa.com/species/white-milkweed/ --- # Whitestem Milkweed (Asclepias albicans) > The tallest milkweed in North America: chalk-white, essentially leafless stems rising to ten feet from rocky desert slopes in the Sonoran Desert, tipped with clusters of cream flowers in late winter. Source: https://milkweedusa.com/species/whitestem-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary The tallest milkweed in North America: chalk-white, essentially leafless stems rising to ten feet from rocky desert slopes in the Sonoran Desert, tipped with clusters of cream flowers in late winter. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias albicans S. Watson | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Whitestem Milkweed, White-stemmed Milkweed, Wax Milkweed | | Status | Native | | Height | 3 ft–10 ft | | Spread | 2 ft–4 ft | | Flower color | cream, white | | Bloom period | January to May and November to December | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 9-11 | | Leaf arrangement | opposite | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, California, Nevada | ## Identification - Very tall, wand-like, waxy white stems in a clump. - Leaves tiny and quickly deciduous, so the plant looks leafless. - Blooms in winter and early spring, unusually for the genus. ## Ecology A winter-flowering desert nectar source of real value when almost nothing else is in bloom. ## Growing A dramatic specimen for frost-free desert gardens; needs rocky drainage and full exposure. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:21135-2 - GBIF: https://www.gbif.org/species/3170348 - iNaturalist: https://www.inaturalist.org/taxa/62299 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_albicans - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20albicans.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20albicans ## Photographs - Asclepias-albicans (NPS, Public domain): https://commons.wikimedia.org/wiki/File:Asclepias-albicans.jpg - Whitestem Milkweed photographed in La Paz, MX-BS, MX (Abraham Sánchez Romero, CC BY 4.0): https://www.inaturalist.org/observations/66636663 - Whitestem Milkweed photographed in Loreto, MX-BS, MX (Sula Vanderplank, CC BY 4.0): https://www.inaturalist.org/observations/99973689 - Whitestem Milkweed photographed in Indio, CA, US (Henrik Kibak, CC BY 4.0): https://www.inaturalist.org/observations/148074612 - Whitestem Milkweed photographed in San Diego County, US-CA, US (W. Terry Hunefeld, CC BY 4.0): https://www.inaturalist.org/observations/9079418 - Whitestem Milkweed photographed in Felicity, CA 92283, USA (Bob Miller, CC BY 4.0): https://www.inaturalist.org/observations/268335420 - Whitestem Milkweed photographed in San Diego County, US-CA, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/202127524 - Whitestem Milkweed photographed in Riverside, California, United States (Matt Berger, CC BY 4.0): https://www.inaturalist.org/observations/150753876 ## How to cite Milkweed USA. (2026). Whitestem Milkweed (Asclepias albicans). https://milkweedusa.com/species/whitestem-milkweed/ --- # Whorled Milkweed (Asclepias verticillata) > A wiry, fine-textured milkweed that looks more like a horsetail than an Asclepias, with needle-thin leaves in whorls up a slim stem and small greenish-white flowers late in the season. It slips into thin, poor, dry ground where nothing else will grow. Source: https://milkweedusa.com/species/whorled-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A wiry, fine-textured milkweed that looks more like a horsetail than an Asclepias, with needle-thin leaves in whorls up a slim stem and small greenish-white flowers late in the season. It slips into thin, poor, dry ground where nothing else will grow. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias verticillata L. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Whorled Milkweed, Eastern Whorled Milkweed, Horsetail Milkweed | | Status | Native | | Height | 1 ft–2.5 ft | | Spread | 9 in–1.5 ft | | Flower color | white, green | | Bloom period | June to September | | Light | Full sun | | Soil moisture | Dry, Average | | USDA zones | 3-9 | | Leaf arrangement | whorled | | Leaf shape | threadlike | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 4 | | US states recorded | Alabama, Arkansas, Arizona, Colorado, Connecticut, District of Columbia, Delaware, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Michigan, Minnesota, Missouri, Mississippi, Montana, North Carolina, North Dakota, Nebraska, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Virginia, Vermont, Wisconsin, West Virginia, Wyoming | ## Identification - Leaves are thread-fine, one to two millimeters wide, arranged in whorls of three to six around the stem. - The whole plant is slender and grass-like until it flowers. - Small white to greenish flowers in several small clusters along the upper stem. - Blooms notably late, often the last milkweed still in flower. ## Ecology A favorite of small native bees and predatory wasps, and a reliable late host for monarch larvae after the big species have gone tough and seedy. Its thin leaves dry quickly, so caterpillars often need several plants. ## Growing Thrives on drought, gravel, thin soil and neglect. It spreads by slender rhizomes and self-sows freely, so treat it as a filler in a prairie planting rather than a specimen. Very easy from seed with a month of cold stratification. ## Cautions Among the more toxic milkweeds to livestock relative to its size, because the whorled-leaved species concentrate cardenolides. Not a plant for a grazed paddock. ## Questions **Is whorled milkweed poisonous to livestock?** Yes. The narrow-leaved whorled milkweeds carry higher cardenolide concentrations by weight than broad-leaved species, and poisoning cases in sheep, cattle and horses are documented, usually from contaminated hay. Keep it out of pasture and hay ground. **Will whorled milkweed take over my garden?** It runs modestly by rhizome and seeds itself, but it is thin and easy to pull. In a dry prairie planting that is a feature, not a problem. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94722-1 - GBIF: https://www.gbif.org/species/3170235 - iNaturalist: https://www.inaturalist.org/taxa/125379 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_verticillata - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20verticillata.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20verticillata ## Photographs - Asclepias verticillata leaves (Choess, CC BY-SA 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_verticillata_leaves.jpg - Asclepias verticillata flower cluster (Mark Fickett, CC BY 3.0): https://commons.wikimedia.org/wiki/File:Asclepias_verticillata_flower_cluster.jpg - Monarch (Danaus plexippus) on Whorled Milkweed (Asclepias verticillata) (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Monarch_(Danaus_plexippus)_on_Whorled_Milkweed_(Asclepias_verticillata).jpg - Monarch (Danaus plexippus) on Whorled Milkweed (Asclepias verticillata) - 6182061536 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Monarch_(Danaus_plexippus)_on_Whorled_Milkweed_(Asclepias_verticillata)_-_6182061536.jpg - Monarch (Danaus plexippus) on Whorled Milkweed (Asclepias verticillata) - 6181540495 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Monarch_(Danaus_plexippus)_on_Whorled_Milkweed_(Asclepias_verticillata)_-_6181540495.jpg - Monarch (Danaus plexippus) on Whorled Milkweed (Asclepias verticillata) - 6181545019 (wackybadger, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Monarch_(Danaus_plexippus)_on_Whorled_Milkweed_(Asclepias_verticillata)_-_6181545019.jpg - Asclepias verticillata (3197723098) (George F Mayfield, CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_verticillata_(3197723098).jpg - Asclepias verticillata (9369383148) (Joshua Mayer (wackybadger), CC BY-SA 2.0): https://commons.wikimedia.org/wiki/File:Asclepias_verticillata_(9369383148).jpg ## How to cite Milkweed USA. (2026). Whorled Milkweed (Asclepias verticillata). https://milkweedusa.com/species/whorled-milkweed/ --- # Woolly Milkweed (Asclepias lanuginosa) > A tiny, shaggy-haired prairie milkweed only a few inches tall, with one cream flower cluster held on a short stalk. Conservation-listed across most of the upper Midwest. Source: https://milkweedusa.com/species/woolly-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A tiny, shaggy-haired prairie milkweed only a few inches tall, with one cream flower cluster held on a short stalk. Conservation-listed across most of the upper Midwest. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias lanuginosa Nutt. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Woolly Milkweed, Side-cluster Milkweed | | Status | Native; rare or legally protected in part of its range | | Height | 4 in–1 ft | | Spread | 6 in–1 ft | | Flower color | cream, green | | Bloom period | May to June | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 3-7 | | Leaf arrangement | alternate | | Leaf shape | lanceolate | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 60 days cold-moist | | Monarch value (0-5) | 2 | | Garden value (0-5) | 1 | | Nectar value (0-5) | 2 | | US states recorded | Iowa, Illinois, Kansas, Michigan, Minnesota, Missouri, North Dakota, Nebraska, South Dakota, Wisconsin | ## Identification - Densely covered in long soft hairs throughout. - Very short stature with a single cream-green flower cluster. - Dry gravel prairie and hill prairie remnants. ## Ecology A dry-prairie remnant indicator, lost wherever prairie has been converted or heavily grazed. ## Growing Rare and difficult; leave wild populations undisturbed. ## Cautions Listed as threatened or endangered in several Midwestern states. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:329557-2 - GBIF: https://www.gbif.org/species/3170327 - iNaturalist: https://www.inaturalist.org/taxa/158745 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_lanuginosa - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20lanuginosa.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20lanuginosa ## Photographs - Near Aden Malpais - Flickr - aspidoscelis (1) (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Near_Aden_Malpais_-_Flickr_-_aspidoscelis_(1).jpg - Lordsburg Mesa - Flickr - aspidoscelis (64) (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Lordsburg_Mesa_-_Flickr_-_aspidoscelis_(64).jpg - Near 1117 Mountain - Flickr - aspidoscelis (3) (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Near_1117_Mountain_-_Flickr_-_aspidoscelis_(3).jpg - Lordsburg Mesa - Flickr - aspidoscelis (94) (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Lordsburg_Mesa_-_Flickr_-_aspidoscelis_(94).jpg - Woolly Milkweed photographed in Wisconsin, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/127321283 - Woolly Milkweed photographed in Fertile, MN, US (Rose Zappa, CC BY 4.0): https://www.inaturalist.org/observations/123310478 - Woolly Milkweed photographed in Juneau County, WI, USA (Kim, CC BY 4.0): https://www.inaturalist.org/observations/290644498 - Woolly Milkweed photographed in Brown County, NE, USA (Colin Croft, CC BY 4.0): https://www.inaturalist.org/observations/27220224 ## How to cite Milkweed USA. (2026). Woolly Milkweed (Asclepias lanuginosa). https://milkweedusa.com/species/woolly-milkweed/ --- # Woolly Milkweed (Asclepias vestita) > A low, densely white-woolly milkweed of California’s San Joaquin Valley and adjacent desert edges, with crowded pale yellow-cream flowers and thick felted leaves. Source: https://milkweedusa.com/species/woolly-milkweed-vestita/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A low, densely white-woolly milkweed of California’s San Joaquin Valley and adjacent desert edges, with crowded pale yellow-cream flowers and thick felted leaves. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias vestita Hook. & Arn. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Woolly Milkweed, Vestita Milkweed | | Status | Native | | Height | 1 ft–3 ft | | Spread | 1.5 ft–2.5 ft | | Flower color | cream, yellow | | Bloom period | April to July | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 8-10 | | Leaf arrangement | alternate | | Leaf shape | oblong | | Sap | Milky latex | | Root system | Deep taproot, resents transplanting | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 3 | | Garden value (0-5) | 2 | | Nectar value (0-5) | 2 | | US states recorded | California, Nevada | ## Identification - Heavily white-woolly throughout, often looking almost gray-white. - Leaves broad, thick and crowded along sprawling stems. - Pale cream to yellowish flowers in tight clusters. ## Ecology A host in the hot interior valleys where few other milkweeds persist through summer. ## Growing Rarely cultivated; needs heat, sun and no summer irrigation. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94723-1 - GBIF: https://www.gbif.org/species/3170336 - iNaturalist: https://www.inaturalist.org/taxa/58529 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_vestita - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20vestita.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20vestita ## Photographs - Asclepias vestita (Chloe and Trevor Van Loon, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_vestita.jpg - (Asclepias vestita in California, envelope IE03-131) - DPLA - 2f9e7b02bb8344f7df91d05efb8cdaa1 (Carlquist, Sherwin John, 1930-2021, CC BY 4.0): https://commons.wikimedia.org/wiki/File:(Asclepias_vestita_in_California,_envelope_IE03-131)_-_DPLA_-_2f9e7b02bb8344f7df91d05efb8cdaa1.jpg - (Asclepias vestita in California, envelope IE03-132) - DPLA - c3afaf4bcb4a091e9bd636f7b419ce11 (Carlquist, Sherwin John, 1930-2021, CC BY 4.0): https://commons.wikimedia.org/wiki/File:(Asclepias_vestita_in_California,_envelope_IE03-132)_-_DPLA_-_c3afaf4bcb4a091e9bd636f7b419ce11.jpg - Woolly Milkweed photographed in Madera County, US-CA, US (Public domain (CC0), CC0): https://www.inaturalist.org/observations/84324641 - Woolly Milkweed photographed in Mariposa, CA, US (wonton_soup, CC BY 4.0): https://www.inaturalist.org/observations/278895644 - Woolly Milkweed photographed in Pinnacles National Park, Paicines, CA, US (Pinnacles National Park, CC BY 4.0): https://www.inaturalist.org/observations/13701289 - Woolly Milkweed photographed in Piñon Hills, CA 92372, USA (Wendy Walker, CC BY 4.0): https://www.inaturalist.org/observations/370216551 - Woolly Milkweed photographed in San Luis Obispo County, CA, USA (Trevor Van Loon, CC BY 4.0): https://www.inaturalist.org/observations/163480362 ## How to cite Milkweed USA. (2026). Woolly Milkweed (Asclepias vestita). https://milkweedusa.com/species/woolly-milkweed-vestita/ --- # Woollypod Milkweed (Asclepias eriocarpa) > A stout, woolly, cream-flowered California milkweed of dry hillsides and roadsides, with thick whorled leaves and densely hairy pods. Historically the most important fiber plant of several California Indigenous nations. Source: https://milkweedusa.com/species/woollypod-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A stout, woolly, cream-flowered California milkweed of dry hillsides and roadsides, with thick whorled leaves and densely hairy pods. Historically the most important fiber plant of several California Indigenous nations. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias eriocarpa Benth. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Woollypod Milkweed, Indian Milkweed, Kotolo | | Status | Native | | Height | 2 ft–4 ft | | Spread | 1.5 ft–3 ft | | Flower color | cream, white | | Bloom period | May to August | | Light | Full sun | | Soil moisture | Dry | | USDA zones | 7-10 | | Leaf arrangement | whorled | | Leaf shape | oblong | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 4 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | California, Nevada | ## Identification - Thick, wavy-edged leaves usually in whorls of three or four. - Dense clusters of cream-white flowers with a waxy look. - Pods conspicuously covered in white wool. ## Ecology A major western monarch host across California’s interior valleys and foothills, and unusually high in cardenolides, which gives its larvae strong chemical defense. ## Growing Drought-tolerant and long-lived, but coarse. Best in wilder parts of a California garden. ## Cautions One of the most toxic North American milkweeds to livestock. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94258-1 - GBIF: https://www.gbif.org/species/3170253 - iNaturalist: https://www.inaturalist.org/taxa/58796 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_eriocarpa - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20eriocarpa.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20eriocarpa ## Photographs - Woolypod milkweed (Asclepias eriocarpa) (27117131095) (Pacific Southwest Region USFWS from Sacramento, US, Public domain): https://commons.wikimedia.org/wiki/File:Woolypod_milkweed_(Asclepias_eriocarpa)_(27117131095).jpg - J20160707-0135—Asclepias eriocarpa-w Apis mellifera—RPBG (27695833984) (John Rusk from Berkeley, CA, United States of America, CC BY 2.0): https://commons.wikimedia.org/wiki/File:J20160707-0135%E2%80%94Asclepias_eriocarpa-w_Apis_mellifera%E2%80%94RPBG_(27695833984).jpg - H20140611-2884—Asclepias eriocarpa—RPBG (14445162271) (John Rusk from Berkeley, CA, United States of America, CC BY 2.0): https://commons.wikimedia.org/wiki/File:H20140611-2884%E2%80%94Asclepias_eriocarpa%E2%80%94RPBG_(14445162271).jpg - H20140611-2881—Asclepias eriocarpa—RPBG (14425400016) (John Rusk from Berkeley, CA, United States of America, CC BY 2.0): https://commons.wikimedia.org/wiki/File:H20140611-2881%E2%80%94Asclepias_eriocarpa%E2%80%94RPBG_(14425400016).jpg - J20170706-0075—Asclepias eriocarpa w Apis mellifera—RPBG—DxO (35098012733) (John Rusk from Berkeley, CA, United States of America, CC BY 2.0): https://commons.wikimedia.org/wiki/File:J20170706-0075%E2%80%94Asclepias_eriocarpa_w_Apis_mellifera%E2%80%94RPBG%E2%80%94DxO_(35098012733).jpg - Asclepias eriocarpa kz01 (Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_eriocarpa_kz01.jpg - Woollypod milkweed plant (15813704011) (Pacific Southwest Region USFWS from Sacramento, US, Public domain): https://commons.wikimedia.org/wiki/File:Woollypod_milkweed_plant_(15813704011).jpg - Asclepiaseriocarpa (Anthony Valois, Public domain): https://commons.wikimedia.org/wiki/File:Asclepiaseriocarpa.jpg ## How to cite Milkweed USA. (2026). Woollypod Milkweed (Asclepias eriocarpa). https://milkweedusa.com/species/woollypod-milkweed/ --- # Zizotes Milkweed (Asclepias oenotheroides) > A low, sprawling Texas and Southwest milkweed with wavy-edged leaves and greenish-cream flower clusters arising from the leaf axils. It blooms for most of the year and re-sprouts endlessly after mowing, which makes it one of the most reliable monarch hosts on the southern plains. Source: https://milkweedusa.com/species/zizotes-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## Summary A low, sprawling Texas and Southwest milkweed with wavy-edged leaves and greenish-cream flower clusters arising from the leaf axils. It blooms for most of the year and re-sprouts endlessly after mowing, which makes it one of the most reliable monarch hosts on the southern plains. ## Key facts | Field | Value | | --- | --- | | Scientific name | Asclepias oenotheroides Schltdl. & Cham. | | Genus | Asclepias | | Family | Apocynaceae | | Common names | Zizotes Milkweed, Side-cluster Milkweed, Hierba de Zizotes | | Status | Native | | Height | 8 in–2 ft | | Spread | 1 ft–2.5 ft | | Flower color | green, cream | | Bloom period | March to October | | Light | Full sun | | Soil moisture | Dry, Average | | USDA zones | 7-10 | | Leaf arrangement | opposite | | Leaf shape | oblong | | Sap | Milky latex | | Root system | Rhizomatous, spreads by root | | Seed stratification | 30 days cold-moist | | Monarch value (0-5) | 5 | | Garden value (0-5) | 3 | | Nectar value (0-5) | 3 | | US states recorded | Arizona, Kansas, New Mexico, Oklahoma, Texas | ## Identification - Flower clusters emerge from the leaf axils along the stem, not just at the tip. - Leaves with distinctly wavy or crinkled margins. - Low sprawling growth, frequently in mown roadsides and lawns. - Hoods are long and slender, projecting well past the corolla. ## Ecology Its long season and tolerance of mowing make it disproportionately important to both the spring and fall monarch migrations through Texas, and it is a mainstay for queen butterflies. ## Growing Tough, drought-proof and quietly spreading. Increasingly offered by Texas native nurseries. ## Cautions Standard milkweed cautions. ## References - Plants of the World Online: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:94504-1 - GBIF: https://www.gbif.org/species/3170282 - iNaturalist: https://www.inaturalist.org/taxa/158753 - Wikipedia: https://en.wikipedia.org/wiki/Asclepias_oenotheroides - BONAP county map: https://bonap.net/MapGallery/County/Asclepias%20oenotheroides.png - NatureServe: https://explorer.natureserve.org/Search?searchTerm=Asclepias%20oenotheroides ## Photographs - Asclepias oenotheroides (Tyler Cannon, CC BY 4.0): https://commons.wikimedia.org/wiki/File:Asclepias_oenotheroides.jpg - Asclepias oenotheroides - Flickr - aspidoscelis (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_oenotheroides_-_Flickr_-_aspidoscelis.jpg - Asclepias oenotheroides - Flickr - aspidoscelis (1) (Patrick Alexander from Las Cruces, NM, CC0): https://commons.wikimedia.org/wiki/File:Asclepias_oenotheroides_-_Flickr_-_aspidoscelis_(1).jpg - Zizotes Milkweed photographed in 32.3717 -106.8718 (Public domain (CC0), CC0): https://www.inaturalist.org/observations/9258486 - Zizotes Milkweed photographed in Texas, US (Michelle W. （鍾偉瑋）, CC BY 4.0): https://www.inaturalist.org/observations/41213291 - Zizotes Milkweed photographed in Nuevo Laredo, MX-TM, MX (Oscar Israel Rodríguez Ortiz, CC BY 4.0): https://www.inaturalist.org/observations/325907228 - Zizotes Milkweed photographed in Southwestern University, Georgetown, TX, US (Sophia K, CC BY 4.0): https://www.inaturalist.org/observations/34145372 - Zizotes Milkweed photographed in Junction, TX 76849, USA (Cleveland Powell, CC BY 4.0): https://www.inaturalist.org/observations/364434469 ## How to cite Milkweed USA. (2026). Zizotes Milkweed (Asclepias oenotheroides). https://milkweedusa.com/species/zizotes-milkweed/ --- # Milkweed in Alaska > 0 milkweed species are recorded in Alaska. Source: https://milkweedusa.com/states/alaska/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Alaska has no native milkweed. The state lies far outside the range of every Asclepias species, and monarch butterflies are not resident here; the handful of records are wind-blown strays. Gardeners wanting to help pollinators should plant native fireweed, willows and Alaskan asters instead. - Species recorded: 0 - USDA hardiness zones: 1–8 - Monarch flyway: none - Best time to sow seed outdoors: October to December, so the seed uses winter rain ## Species No Asclepias species are native to Alaska. ## How to cite Milkweed USA. (2026). Milkweed in Alaska. https://milkweedusa.com/states/alaska/ --- # Milkweed in Maine > 5 milkweed species are recorded in Maine. Source: https://milkweedusa.com/states/maine/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Maine sits at the northeastern edge of the monarch breeding range, where common milkweed colonizes old fields, blueberry barrens and roadsides. Coastal fog and a short season mean plants leaf out late but grow lush; swamp milkweed thrives along the state’s abundant wetland margins. - Species recorded: 5 - USDA hardiness zones: 3b–6a - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Maine | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | ## How to cite Milkweed USA. (2026). Milkweed in Maine. https://milkweedusa.com/states/maine/ --- # Milkweed in Vermont > 7 milkweed species are recorded in Vermont. Source: https://milkweedusa.com/states/vermont/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Vermont’s hayfields, hedgerows and river floodplains carry dense stands of common milkweed, and the Champlain Valley is one of New England’s most productive monarch breeding landscapes. Late-cut hay meadows are the single biggest thing a Vermont landowner can offer the species. - Species recorded: 7 - USDA hardiness zones: 3b–5b - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Vermont | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in Vermont. https://milkweedusa.com/states/vermont/ --- # Milkweed in New Hampshire > 8 milkweed species are recorded in New Hampshire. Source: https://milkweedusa.com/states/new-hampshire/ Licence: CC BY 4.0 (Milkweed USA) ## Overview From the Merrimack Valley to the White Mountain foothills, New Hampshire’s milkweeds are concentrated in old fields and powerline corridors below about 2,000 feet. Poke milkweed appears along shaded woodland edges where the common species will not grow. - Species recorded: 8 - USDA hardiness zones: 3b–6a - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in New Hampshire | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in New Hampshire. https://milkweedusa.com/states/new-hampshire/ --- # Milkweed in Washington > 3 milkweed species are recorded in Washington. Source: https://milkweedusa.com/states/washington/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Nearly all of Washington’s milkweed is east of the Cascades, where showy milkweed lines irrigation ditches and the Columbia Basin’s shrub-steppe supports narrowleaf milkweed. Western Washington has very little native milkweed and correspondingly few breeding monarchs. - Species recorded: 3 - USDA hardiness zones: 4a–9a - Monarch flyway: western - Best time to sow seed outdoors: October to December, so the seed uses winter rain ## Species recorded in Washington | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Narrowleaf Milkweed | Asclepias fascicularis | Yes | 2 ft–4 ft | May to September | | Pallid Milkweed | Asclepias cryptoceras | Yes | 4 in–1 ft | April to June | ## How to cite Milkweed USA. (2026). Milkweed in Washington. https://milkweedusa.com/states/washington/ --- # Milkweed in Idaho > 3 milkweed species are recorded in Idaho. Source: https://milkweedusa.com/states/idaho/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Showy milkweed follows the Snake River Plain and its irrigation network across southern Idaho, forming the state’s main monarch breeding habitat. Pallid milkweed turns up on dry clay barrens in the southwest corner. - Species recorded: 3 - USDA hardiness zones: 3a–7a - Monarch flyway: western - Best time to sow seed outdoors: September to November, before the ground freezes ## Species recorded in Idaho | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Narrowleaf Milkweed | Asclepias fascicularis | Yes | 2 ft–4 ft | May to September | | Pallid Milkweed | Asclepias cryptoceras | Yes | 4 in–1 ft | April to June | ## How to cite Milkweed USA. (2026). Milkweed in Idaho. https://milkweedusa.com/states/idaho/ --- # Milkweed in Montana > 8 milkweed species are recorded in Montana. Source: https://milkweedusa.com/states/montana/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Montana sits on the divide between eastern and western monarch populations, with showy milkweed along the Yellowstone and Missouri river systems and green comet milkweed on dry prairie. Riparian corridors matter enormously here, being the only reliably moist habitat for hundreds of miles. - Species recorded: 8 - USDA hardiness zones: 3a–6a - Monarch flyway: both - Best time to sow seed outdoors: September to November, before the ground freezes ## Species recorded in Montana | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Oval-leaf Milkweed | Asclepias ovalifolia | Yes | 8 in–1.7 ft | June to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Plains Milkweed | Asclepias pumila | Yes | 4 in–1 ft | June to September | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | ## How to cite Milkweed USA. (2026). Milkweed in Montana. https://milkweedusa.com/states/montana/ --- # Milkweed in North Dakota > 10 milkweed species are recorded in North Dakota. Source: https://milkweedusa.com/states/north-dakota/ Licence: CC BY 4.0 (Milkweed USA) ## Overview North Dakota produces an outsized share of the eastern monarch population relative to its size, with common and showy milkweed abundant in Conservation Reserve Program grassland and prairie potholes. Oval-leaf milkweed occupies sandy prairie in the eastern counties. - Species recorded: 10 - USDA hardiness zones: 3a–4b - Monarch flyway: eastern - Best time to sow seed outdoors: October to November ## Species recorded in North Dakota | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Oval-leaf Milkweed | Asclepias ovalifolia | Yes | 8 in–1.7 ft | June to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Plains Milkweed | Asclepias pumila | Yes | 4 in–1 ft | June to September | | Woolly Milkweed | Asclepias lanuginosa | Yes | 4 in–1 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in North Dakota. https://milkweedusa.com/states/north-dakota/ --- # Milkweed in Minnesota > 13 milkweed species are recorded in Minnesota. Source: https://milkweedusa.com/states/minnesota/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Minnesota is one of the highest-value monarch breeding states in the country, with common milkweed in old fields, swamp milkweed in the state’s countless wetlands and prairie milkweed on remnant tallgrass. Its official state butterfly is the monarch. - Species recorded: 13 - USDA hardiness zones: 3a–5a - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Minnesota | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Oval-leaf Milkweed | Asclepias ovalifolia | Yes | 8 in–1.7 ft | June to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Woolly Milkweed | Asclepias lanuginosa | Yes | 4 in–1 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in Minnesota. https://milkweedusa.com/states/minnesota/ --- # Milkweed in Illinois > 17 milkweed species are recorded in Illinois. Source: https://milkweedusa.com/states/illinois/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Almost all of Illinois’ original tallgrass prairie is now cropland, so its milkweed survives in railroad rights of way, cemetery prairies and roadside ditches. Those remnants hold some of the best populations of prairie milkweed and Mead’s milkweed left anywhere. - Species recorded: 17 - USDA hardiness zones: 5a–7a - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Illinois | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Oval-leaf Milkweed | Asclepias ovalifolia | Yes | 8 in–1.7 ft | June to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Mead’s Milkweed | Asclepias meadii | Yes | 1 ft–2 ft | May to June | | Woolly Milkweed | Asclepias lanuginosa | Yes | 4 in–1 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in Illinois. https://milkweedusa.com/states/illinois/ --- # Milkweed in Wisconsin > 13 milkweed species are recorded in Wisconsin. Source: https://milkweedusa.com/states/wisconsin/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Wisconsin’s sand counties, driftless-area bluff prairies and wetland edges give it more milkweed diversity than most northern states, including oval-leaf, woolly and prairie milkweed. Common milkweed in old dairy pasture remains the backbone of monarch production. - Species recorded: 13 - USDA hardiness zones: 3b–5b - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Wisconsin | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Oval-leaf Milkweed | Asclepias ovalifolia | Yes | 8 in–1.7 ft | June to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Woolly Milkweed | Asclepias lanuginosa | Yes | 4 in–1 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in Wisconsin. https://milkweedusa.com/states/wisconsin/ --- # Milkweed in Michigan > 13 milkweed species are recorded in Michigan. Source: https://milkweedusa.com/states/michigan/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Michigan’s dune systems, oak savanna and old fields support a wide milkweed flora, and the state is a major staging area for fall monarch migration along both peninsulas’ shorelines. Fourleaf and poke milkweed occupy the state’s hardwood forests. - Species recorded: 13 - USDA hardiness zones: 4a–6b - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Michigan | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | Oval-leaf Milkweed | Asclepias ovalifolia | Yes | 8 in–1.7 ft | June to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Woolly Milkweed | Asclepias lanuginosa | Yes | 4 in–1 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in Michigan. https://milkweedusa.com/states/michigan/ --- # Milkweed in New York > 11 milkweed species are recorded in New York. Source: https://milkweedusa.com/states/new-york/ Licence: CC BY 4.0 (Milkweed USA) ## Overview New York runs from Long Island’s pine barrens to the Adirondacks, and its milkweed flora spans that gradient: clasping milkweed in coastal sand, poke milkweed in northern hardwoods, common milkweed everywhere in between. Purple milkweed persists in scattered Hudson Valley remnants. - Species recorded: 11 - USDA hardiness zones: 3b–7b - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in New York | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | ## How to cite Milkweed USA. (2026). Milkweed in New York. https://milkweedusa.com/states/new-york/ --- # Milkweed in Massachusetts > 8 milkweed species are recorded in Massachusetts. Source: https://milkweedusa.com/states/massachusetts/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Massachusetts pairs abundant common milkweed in old fields with specialist sandplain species such as clasping milkweed on Cape Cod and the islands and swamp milkweed along coastal marshes. Sandplain grassland restoration is the state’s highest-leverage monarch work. - Species recorded: 8 - USDA hardiness zones: 5a–7b - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Massachusetts | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in Massachusetts. https://milkweedusa.com/states/massachusetts/ --- # Milkweed in Rhode Island > 8 milkweed species are recorded in Rhode Island. Source: https://milkweedusa.com/states/rhode-island/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Small but well supplied: Rhode Island’s coastal grasslands and old fields carry common, swamp and butterfly milkweed, with clasping milkweed on the sandy south coast. Roadside mowing timing is the key management question in a state this densely settled. - Species recorded: 8 - USDA hardiness zones: 5b–7a - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Rhode Island | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in Rhode Island. https://milkweedusa.com/states/rhode-island/ --- # Milkweed in Oregon > 4 milkweed species are recorded in Oregon. Source: https://milkweedusa.com/states/oregon/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Showy milkweed dominates the Willamette Valley and the state’s eastern high desert, while narrowleaf milkweed occupies southern Oregon’s drier valleys and heartleaf milkweed climbs into the Siskiyou foothills. Oregon is a critical spring corridor for western monarchs leaving the California coast. - Species recorded: 4 - USDA hardiness zones: 4a–9b - Monarch flyway: western - Best time to sow seed outdoors: October to December, so the seed uses winter rain ## Species recorded in Oregon | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Narrowleaf Milkweed | Asclepias fascicularis | Yes | 2 ft–4 ft | May to September | | Heartleaf Milkweed | Asclepias cordifolia | Yes | 1 ft–3 ft | May to July | | Pallid Milkweed | Asclepias cryptoceras | Yes | 4 in–1 ft | April to June | ## How to cite Milkweed USA. (2026). Milkweed in Oregon. https://milkweedusa.com/states/oregon/ --- # Milkweed in Nevada > 18 milkweed species are recorded in Nevada. Source: https://milkweedusa.com/states/nevada/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Nevada’s milkweeds cluster around water, with showy and narrowleaf milkweed along rivers, springs and irrigated valleys, and desert and rush milkweed in the southern Mojave. Pallid milkweed on Great Basin clay barrens is the state’s botanical prize. - Species recorded: 18 - USDA hardiness zones: 4a–9b - Monarch flyway: western - Best time to sow seed outdoors: September to November, before the ground freezes ## Species recorded in Nevada | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Narrowleaf Milkweed | Asclepias fascicularis | Yes | 2 ft–4 ft | May to September | | Heartleaf Milkweed | Asclepias cordifolia | Yes | 1 ft–3 ft | May to July | | Antelope Horns | Asclepias asperula | Yes | 1 ft–2 ft | March to July | | Rush Milkweed | Asclepias subulata | Yes | 2 ft–6 ft | nearly year-round in frost-free areas | | Hall’s Milkweed | Asclepias hallii | Yes | 1.5 ft–3 ft | June to August | | Woollypod Milkweed | Asclepias eriocarpa | Yes | 2 ft–4 ft | May to August | | Desert Milkweed | Asclepias erosa | Yes | 2 ft–5 ft | April to September | | Broadleaf Milkweed | Asclepias latifolia | Yes | 1 ft–3 ft | May to August | | Whitestem Milkweed | Asclepias albicans | Yes | 3 ft–10 ft | January to May and November to December | | Woolly Milkweed | Asclepias vestita | Yes | 1 ft–3 ft | April to July | | Poison Milkweed | Asclepias subverticillata | Yes | 1 ft–3 ft | June to September | | Pallid Milkweed | Asclepias cryptoceras | Yes | 4 in–1 ft | April to June | | Mojave Milkweed | Asclepias nyctaginifolia | Yes | 6 in–1.5 ft | April to June | | Dwarf Milkweed | Asclepias involucrata | Yes | 4 in–10 in | April to June | | Ruth’s Milkweed | Asclepias ruthiae | Yes | 4 in–1 ft | April to June | | Wheel Milkweed | Asclepias uncialis | Yes | 2 in–6 in | April to June | | Eastwood’s Milkweed | Asclepias eastwoodiana | Yes | 6 in–1.2 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in Nevada. https://milkweedusa.com/states/nevada/ --- # Milkweed in Wyoming > 14 milkweed species are recorded in Wyoming. Source: https://milkweedusa.com/states/wyoming/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Showy milkweed follows the North Platte, Bighorn and Green River corridors, and the state’s shortgrass plains hold plains, green comet and Engelmann’s milkweed. Wyoming straddles the eastern and western monarch flyways and its riparian ribbons carry nearly all the breeding. - Species recorded: 14 - USDA hardiness zones: 2b–6a - Monarch flyway: both - Best time to sow seed outdoors: September to November, before the ground freezes ## Species recorded in Wyoming | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Hall’s Milkweed | Asclepias hallii | Yes | 1.5 ft–3 ft | June to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Broadleaf Milkweed | Asclepias latifolia | Yes | 1 ft–3 ft | May to August | | Plains Milkweed | Asclepias pumila | Yes | 4 in–1 ft | June to September | | Engelmann’s Milkweed | Asclepias engelmanniana | Yes | 2 ft–5 ft | June to August | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Poison Milkweed | Asclepias subverticillata | Yes | 1 ft–3 ft | June to September | | Pallid Milkweed | Asclepias cryptoceras | Yes | 4 in–1 ft | April to June | | Wheel Milkweed | Asclepias uncialis | Yes | 2 in–6 in | April to June | ## How to cite Milkweed USA. (2026). Milkweed in Wyoming. https://milkweedusa.com/states/wyoming/ --- # Milkweed in South Dakota > 12 milkweed species are recorded in South Dakota. Source: https://milkweedusa.com/states/south-dakota/ Licence: CC BY 4.0 (Milkweed USA) ## Overview East river, common and prairie milkweed occupy tallgrass remnants and CRP fields; west river, the shortgrass plains support plains, Engelmann’s and green comet milkweed. The Missouri River corridor is the state’s primary monarch highway. - Species recorded: 12 - USDA hardiness zones: 3b–5b - Monarch flyway: eastern - Best time to sow seed outdoors: October to November ## Species recorded in South Dakota | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Oval-leaf Milkweed | Asclepias ovalifolia | Yes | 8 in–1.7 ft | June to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Plains Milkweed | Asclepias pumila | Yes | 4 in–1 ft | June to September | | Engelmann’s Milkweed | Asclepias engelmanniana | Yes | 2 ft–5 ft | June to August | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Woolly Milkweed | Asclepias lanuginosa | Yes | 4 in–1 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in South Dakota. https://milkweedusa.com/states/south-dakota/ --- # Milkweed in Iowa > 16 milkweed species are recorded in Iowa. Source: https://milkweedusa.com/states/iowa/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Iowa produces a disproportionate share of the eastern monarch population, almost entirely from roadside plantings, CRP acres and cemetery prairies in a landscape that is otherwise more than 85 percent cultivated. The state’s integrated roadside vegetation management program is a national model. - Species recorded: 16 - USDA hardiness zones: 4b–6a - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Iowa | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | Oval-leaf Milkweed | Asclepias ovalifolia | Yes | 8 in–1.7 ft | June to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Mead’s Milkweed | Asclepias meadii | Yes | 1 ft–2 ft | May to June | | Woolly Milkweed | Asclepias lanuginosa | Yes | 4 in–1 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in Iowa. https://milkweedusa.com/states/iowa/ --- # Milkweed in Indiana > 14 milkweed species are recorded in Indiana. Source: https://milkweedusa.com/states/indiana/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Indiana’s milkweed is concentrated in the northwest prairie remnants, the Kankakee sand country and southern oak-hickory woodland edges. Poke and fourleaf milkweed occupy the state’s shaded slopes where common milkweed cannot compete. - Species recorded: 14 - USDA hardiness zones: 5b–7a - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Indiana | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | ## How to cite Milkweed USA. (2026). Milkweed in Indiana. https://milkweedusa.com/states/indiana/ --- # Milkweed in Ohio > 12 milkweed species are recorded in Ohio. Source: https://milkweedusa.com/states/ohio/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Ohio’s old fields and reclaimed strip mines carry heavy common milkweed, while the Oak Openings region near Toledo holds unusual sand-prairie species. Lake Erie’s southern shore is a nationally important fall monarch staging area. - Species recorded: 12 - USDA hardiness zones: 5b–6b - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Ohio | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | ## How to cite Milkweed USA. (2026). Milkweed in Ohio. https://milkweedusa.com/states/ohio/ --- # Milkweed in Pennsylvania > 11 milkweed species are recorded in Pennsylvania. Source: https://milkweedusa.com/states/pennsylvania/ Licence: CC BY 4.0 (Milkweed USA) ## Overview From the Allegheny Plateau to the Piedmont, Pennsylvania supports common, swamp, butterfly and poke milkweed, with purple milkweed clinging on in scattered woodland-edge sites. Powerline rights of way managed as meadow are among the state’s best monarch habitat. - Species recorded: 11 - USDA hardiness zones: 5a–7b - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Pennsylvania | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | ## How to cite Milkweed USA. (2026). Milkweed in Pennsylvania. https://milkweedusa.com/states/pennsylvania/ --- # Milkweed in New Jersey > 13 milkweed species are recorded in New Jersey. Source: https://milkweedusa.com/states/new-jersey/ Licence: CC BY 4.0 (Milkweed USA) ## Overview New Jersey’s Pine Barrens support sand specialists such as clasping and fewflower milkweed, while the Delaware Bayshore and Cape May peninsula funnel one of the densest fall monarch migrations on the continent. Cape May’s monarch monitoring project has run since 1990. - Species recorded: 13 - USDA hardiness zones: 6a–7b - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in New Jersey | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | ## How to cite Milkweed USA. (2026). Milkweed in New Jersey. https://milkweedusa.com/states/new-jersey/ --- # Milkweed in Connecticut > 11 milkweed species are recorded in Connecticut. Source: https://milkweedusa.com/states/connecticut/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Connecticut’s milkweed is largely a story of old fields and utility corridors, with swamp milkweed along the Connecticut River floodplain and butterfly weed on dry traprock ridges. Purple and red milkweed are both state-listed rarities here. - Species recorded: 11 - USDA hardiness zones: 5b–7a - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Connecticut | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | ## How to cite Milkweed USA. (2026). Milkweed in Connecticut. https://milkweedusa.com/states/connecticut/ --- # Milkweed in California > 14 milkweed species are recorded in California. Source: https://milkweedusa.com/states/california/ Licence: CC BY 4.0 (Milkweed USA) ## Overview California holds more milkweed species than any other western state: narrowleaf in the Central Valley, heartleaf and California milkweed in the foothills, desert and rush milkweed in the south. Its coastal groves host the entire overwintering western monarch population. Tropical milkweed is a serious problem here and should not be planted. - Species recorded: 14 - USDA hardiness zones: 5a–11a - Monarch flyway: western - Best time to sow seed outdoors: October to December, so the seed uses winter rain ## Species recorded in California | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Narrowleaf Milkweed | Asclepias fascicularis | Yes | 2 ft–4 ft | May to September | | Heartleaf Milkweed | Asclepias cordifolia | Yes | 1 ft–3 ft | May to July | | California Milkweed | Asclepias californica | Yes | 1 ft–3 ft | April to July | | Rush Milkweed | Asclepias subulata | Yes | 2 ft–6 ft | nearly year-round in frost-free areas | | Woollypod Milkweed | Asclepias eriocarpa | Yes | 2 ft–4 ft | May to August | | Desert Milkweed | Asclepias erosa | Yes | 2 ft–5 ft | April to September | | Whitestem Milkweed | Asclepias albicans | Yes | 3 ft–10 ft | January to May and November to December | | Balloon Plant | Gomphocarpus physocarpus | No | 3 ft–6 ft | May to October | | Tropical Milkweed | Asclepias curassavica | No | 2 ft–4 ft | nearly year-round in frost-free areas | | Woolly Milkweed | Asclepias vestita | Yes | 1 ft–3 ft | April to July | | Giant Milkweed | Calotropis procera | No | 6 ft–12 ft | nearly year-round in frost-free areas | | Pallid Milkweed | Asclepias cryptoceras | Yes | 4 in–1 ft | April to June | | Serpentine Milkweed | Asclepias solanoana | Yes | 4 in–10 in | May to July | ## How to cite Milkweed USA. (2026). Milkweed in California. https://milkweedusa.com/states/california/ --- # Milkweed in Utah > 18 milkweed species are recorded in Utah. Source: https://milkweedusa.com/states/utah/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Showy milkweed along the Wasatch Front’s streams and irrigation ditches carries most of Utah’s monarch breeding, with Hall’s, broadleaf and pallid milkweed on the Colorado Plateau’s drier ground. Utah is also home to federally threatened Welsh’s milkweed in the Coral Pink Sand Dunes. - Species recorded: 18 - USDA hardiness zones: 4a–9a - Monarch flyway: western - Best time to sow seed outdoors: September to November, before the ground freezes ## Species recorded in Utah | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Narrowleaf Milkweed | Asclepias fascicularis | Yes | 2 ft–4 ft | May to September | | Antelope Horns | Asclepias asperula | Yes | 1 ft–2 ft | March to July | | Rush Milkweed | Asclepias subulata | Yes | 2 ft–6 ft | nearly year-round in frost-free areas | | Hall’s Milkweed | Asclepias hallii | Yes | 1.5 ft–3 ft | June to August | | Desert Milkweed | Asclepias erosa | Yes | 2 ft–5 ft | April to September | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Broadleaf Milkweed | Asclepias latifolia | Yes | 1 ft–3 ft | May to August | | Sand Milkweed | Asclepias arenaria | Yes | 1 ft–2.5 ft | June to August | | Poison Milkweed | Asclepias subverticillata | Yes | 1 ft–3 ft | June to September | | Pallid Milkweed | Asclepias cryptoceras | Yes | 4 in–1 ft | April to June | | Mojave Milkweed | Asclepias nyctaginifolia | Yes | 6 in–1.5 ft | April to June | | Dwarf Milkweed | Asclepias involucrata | Yes | 4 in–10 in | April to June | | Welsh’s Milkweed | Asclepias welshii | Yes | 1.5 ft–4 ft | May to July | | Ruth’s Milkweed | Asclepias ruthiae | Yes | 4 in–1 ft | April to June | | Wheel Milkweed | Asclepias uncialis | Yes | 2 in–6 in | April to June | ## How to cite Milkweed USA. (2026). Milkweed in Utah. https://milkweedusa.com/states/utah/ --- # Milkweed in Colorado > 19 milkweed species are recorded in Colorado. Source: https://milkweedusa.com/states/colorado/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Colorado is one of the most milkweed-diverse states in the West, with roughly twenty species spanning shortgrass plains, foothills, mesas and the Western Slope. Showy milkweed along the South Platte and Arkansas river corridors does most of the monarch work, while the eastern plains hold rarities such as wheel milkweed found almost nowhere else. - Species recorded: 19 - USDA hardiness zones: 3a–7a - Monarch flyway: both - Best time to sow seed outdoors: September to November, before the ground freezes ## Species recorded in Colorado | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Antelope Horns | Asclepias asperula | Yes | 1 ft–2 ft | March to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Hall’s Milkweed | Asclepias hallii | Yes | 1.5 ft–3 ft | June to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Broadleaf Milkweed | Asclepias latifolia | Yes | 1 ft–3 ft | May to August | | Sand Milkweed | Asclepias arenaria | Yes | 1 ft–2.5 ft | June to August | | Plains Milkweed | Asclepias pumila | Yes | 4 in–1 ft | June to September | | Engelmann’s Milkweed | Asclepias engelmanniana | Yes | 2 ft–5 ft | June to August | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Poison Milkweed | Asclepias subverticillata | Yes | 1 ft–3 ft | June to September | | Pallid Milkweed | Asclepias cryptoceras | Yes | 4 in–1 ft | April to June | | Dwarf Milkweed | Asclepias involucrata | Yes | 4 in–10 in | April to June | | Longhood Milkweed | Asclepias macrotis | Yes | 8 in–1.7 ft | April to August | | Wheel Milkweed | Asclepias uncialis | Yes | 2 in–6 in | April to June | ## How to cite Milkweed USA. (2026). Milkweed in Colorado. https://milkweedusa.com/states/colorado/ --- # Milkweed in Nebraska > 20 milkweed species are recorded in Nebraska. Source: https://milkweedusa.com/states/nebraska/ Licence: CC BY 4.0 (Milkweed USA) ## Overview The Nebraska Sandhills are one of the largest intact grasslands in North America and hold sand, plains and green comet milkweed alongside abundant common and showy milkweed. The Platte River corridor is a continentally significant migration route. - Species recorded: 20 - USDA hardiness zones: 4a–6a - Monarch flyway: eastern - Best time to sow seed outdoors: October to November ## Species recorded in Nebraska | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Antelope Horns | Asclepias asperula | Yes | 1 ft–2 ft | March to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Oval-leaf Milkweed | Asclepias ovalifolia | Yes | 8 in–1.7 ft | June to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Broadleaf Milkweed | Asclepias latifolia | Yes | 1 ft–3 ft | May to August | | Sand Milkweed | Asclepias arenaria | Yes | 1 ft–2.5 ft | June to August | | Plains Milkweed | Asclepias pumila | Yes | 4 in–1 ft | June to September | | Engelmann’s Milkweed | Asclepias engelmanniana | Yes | 2 ft–5 ft | June to August | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Poison Milkweed | Asclepias subverticillata | Yes | 1 ft–3 ft | June to September | | Woolly Milkweed | Asclepias lanuginosa | Yes | 4 in–1 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in Nebraska. https://milkweedusa.com/states/nebraska/ --- # Milkweed in Missouri > 17 milkweed species are recorded in Missouri. Source: https://milkweedusa.com/states/missouri/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Missouri’s glades, Ozark woodlands and prairie remnants give it exceptional milkweed diversity for a Midwestern state, including green antelopehorn, purple milkweed and federally threatened Mead’s milkweed. Kansas City and St Louis both run large-scale urban monarch habitat programs. - Species recorded: 17 - USDA hardiness zones: 5b–7a - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Missouri | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Mead’s Milkweed | Asclepias meadii | Yes | 1 ft–2 ft | May to June | | Woolly Milkweed | Asclepias lanuginosa | Yes | 4 in–1 ft | May to June | ## How to cite Milkweed USA. (2026). Milkweed in Missouri. https://milkweedusa.com/states/missouri/ --- # Milkweed in Kentucky > 15 milkweed species are recorded in Kentucky. Source: https://milkweedusa.com/states/kentucky/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Kentucky’s Bluegrass pastures, Pennyroyal barrens and Appalachian woodland edges support common, butterfly, purple and white milkweed. The state’s remnant limestone glades are the best place to find green comet and clasping milkweed. - Species recorded: 15 - USDA hardiness zones: 6a–7a - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in Kentucky | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | ## How to cite Milkweed USA. (2026). Milkweed in Kentucky. https://milkweedusa.com/states/kentucky/ --- # Milkweed in West Virginia > 10 milkweed species are recorded in West Virginia. Source: https://milkweedusa.com/states/west-virginia/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Steep and heavily forested, West Virginia’s milkweed lives on reclaimed mine land, ridgetop pasture and woodland edge. Poke, fourleaf and white milkweed are all genuinely at home in the state’s Appalachian forests. - Species recorded: 10 - USDA hardiness zones: 5a–7a - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in West Virginia | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | ## How to cite Milkweed USA. (2026). Milkweed in West Virginia. https://milkweedusa.com/states/west-virginia/ --- # Milkweed in Virginia > 14 milkweed species are recorded in Virginia. Source: https://milkweedusa.com/states/virginia/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Virginia spans Coastal Plain sand, Piedmont clay and Appalachian ridge, and its milkweed flora follows suit: fewflower and longleaf milkweed near the coast, white and fourleaf milkweed in the mountains, common milkweed throughout. Purple and red milkweed are both state rarities. - Species recorded: 14 - USDA hardiness zones: 5a–8a - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in Virginia | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | ## How to cite Milkweed USA. (2026). Milkweed in Virginia. https://milkweedusa.com/states/virginia/ --- # Milkweed in Maryland > 13 milkweed species are recorded in Maryland. Source: https://milkweedusa.com/states/maryland/ Licence: CC BY 4.0 (Milkweed USA) ## Overview From the Eastern Shore’s marshes to the western mountains, Maryland packs a lot of habitat into a small area, with swamp and fewflower milkweed in tidal wetlands and butterfly weed on Piedmont serpentine barrens. The serpentine grasslands of Soldiers Delight are a regional milkweed hotspot. - Species recorded: 13 - USDA hardiness zones: 5b–8a - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in Maryland | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | ## How to cite Milkweed USA. (2026). Milkweed in Maryland. https://milkweedusa.com/states/maryland/ --- # Milkweed in Delaware > 13 milkweed species are recorded in Delaware. Source: https://milkweedusa.com/states/delaware/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Delaware’s coastal plain sands and tidal marshes support clasping, fewflower and swamp milkweed, and the Delaware Bayshore is a major fall monarch staging area. Nearly the whole state is within a few feet of sea level, so wetland species dominate. - Species recorded: 13 - USDA hardiness zones: 7a–7b - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in Delaware | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | ## How to cite Milkweed USA. (2026). Milkweed in Delaware. https://milkweedusa.com/states/delaware/ --- # Milkweed in Arizona > 31 milkweed species are recorded in Arizona. Source: https://milkweedusa.com/states/arizona/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Arizona’s milkweed flora is the most distinctive in the country, with leafless rush milkweed and towering whitestem milkweed in the Sonoran Desert, pineneedle milkweed on desert grassland, and showy milkweed along mountain streams. Many species bloom in winter or after summer monsoon rain rather than in spring. - Species recorded: 31 - USDA hardiness zones: 4b–10b - Monarch flyway: western - Best time to sow seed outdoors: November to January ## Species recorded in Arizona | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Narrowleaf Milkweed | Asclepias fascicularis | Yes | 2 ft–4 ft | May to September | | Antelope Horns | Asclepias asperula | Yes | 1 ft–2 ft | March to July | | Rush Milkweed | Asclepias subulata | Yes | 2 ft–6 ft | nearly year-round in frost-free areas | | Zizotes Milkweed | Asclepias oenotheroides | Yes | 8 in–2 ft | March to October | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Hall’s Milkweed | Asclepias hallii | Yes | 1.5 ft–3 ft | June to August | | Desert Milkweed | Asclepias erosa | Yes | 2 ft–5 ft | April to September | | Pineneedle Milkweed | Asclepias linaria | Yes | 1.5 ft–4 ft | March to October | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Broadleaf Milkweed | Asclepias latifolia | Yes | 1 ft–3 ft | May to August | | Sand Milkweed | Asclepias arenaria | Yes | 1 ft–2.5 ft | June to August | | Whitestem Milkweed | Asclepias albicans | Yes | 3 ft–10 ft | January to May and November to December | | Mahogany Milkweed | Asclepias hypoleuca | Yes | 1 ft–2.5 ft | June to September | | Nodding Milkweed | Asclepias glaucescens | Yes | 1 ft–3 ft | June to September | | Tropical Milkweed | Asclepias curassavica | No | 2 ft–4 ft | nearly year-round in frost-free areas | | Bract Milkweed | Asclepias brachystephana | Yes | 6 in–1.5 ft | April to August | | Rusby’s Milkweed | Asclepias rusbyi | Yes | 1 ft–2.5 ft | May to August | | Giant Milkweed | Calotropis procera | No | 6 ft–12 ft | nearly year-round in frost-free areas | | Poison Milkweed | Asclepias subverticillata | Yes | 1 ft–3 ft | June to September | | Pallid Milkweed | Asclepias cryptoceras | Yes | 4 in–1 ft | April to June | | Mojave Milkweed | Asclepias nyctaginifolia | Yes | 6 in–1.5 ft | April to June | | Dwarf Milkweed | Asclepias involucrata | Yes | 4 in–10 in | April to June | | Longhood Milkweed | Asclepias macrotis | Yes | 8 in–1.7 ft | April to August | | Welsh’s Milkweed | Asclepias welshii | Yes | 1.5 ft–4 ft | May to July | | Ruth’s Milkweed | Asclepias ruthiae | Yes | 4 in–1 ft | April to June | | Lemmon’s Milkweed | Asclepias lemmonii | Yes | 8 in–2 ft | July to September | | Slimpod Milkweed | Asclepias quinquedentata | Yes | 1 ft–2.5 ft | July to September | | Wheel Milkweed | Asclepias uncialis | Yes | 2 in–6 in | April to June | | Tufted Milkweed | Asclepias nummularia | Yes | 2 in–8 in | April to August | ## How to cite Milkweed USA. (2026). Milkweed in Arizona. https://milkweedusa.com/states/arizona/ --- # Milkweed in New Mexico > 29 milkweed species are recorded in New Mexico. Source: https://milkweedusa.com/states/new-mexico/ Licence: CC BY 4.0 (Milkweed USA) ## Overview New Mexico may hold more milkweed species than any other state, with antelope horns and broadleaf milkweed on the plains, pineneedle and bract milkweed in the Chihuahuan Desert, and showy milkweed along the Rio Grande. The state sits on the boundary between eastern and western monarch flyways. - Species recorded: 29 - USDA hardiness zones: 4a–9a - Monarch flyway: both - Best time to sow seed outdoors: November to January ## Species recorded in New Mexico | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Antelope Horns | Asclepias asperula | Yes | 1 ft–2 ft | March to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Zizotes Milkweed | Asclepias oenotheroides | Yes | 8 in–2 ft | March to October | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Hall’s Milkweed | Asclepias hallii | Yes | 1.5 ft–3 ft | June to August | | Pineneedle Milkweed | Asclepias linaria | Yes | 1.5 ft–4 ft | March to October | | Texas Milkweed | Asclepias texana | Yes | 1 ft–3 ft | May to September | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Broadleaf Milkweed | Asclepias latifolia | Yes | 1 ft–3 ft | May to August | | Sand Milkweed | Asclepias arenaria | Yes | 1 ft–2.5 ft | June to August | | Mahogany Milkweed | Asclepias hypoleuca | Yes | 1 ft–2.5 ft | June to September | | Nodding Milkweed | Asclepias glaucescens | Yes | 1 ft–3 ft | June to September | | Plains Milkweed | Asclepias pumila | Yes | 4 in–1 ft | June to September | | Engelmann’s Milkweed | Asclepias engelmanniana | Yes | 2 ft–5 ft | June to August | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Bract Milkweed | Asclepias brachystephana | Yes | 6 in–1.5 ft | April to August | | Rusby’s Milkweed | Asclepias rusbyi | Yes | 1 ft–2.5 ft | May to August | | Poison Milkweed | Asclepias subverticillata | Yes | 1 ft–3 ft | June to September | | Pallid Milkweed | Asclepias cryptoceras | Yes | 4 in–1 ft | April to June | | Mojave Milkweed | Asclepias nyctaginifolia | Yes | 6 in–1.5 ft | April to June | | Emory’s Milkweed | Asclepias emoryi | Yes | 4 in–1.2 ft | April to September | | Dwarf Milkweed | Asclepias involucrata | Yes | 4 in–10 in | April to June | | Longhood Milkweed | Asclepias macrotis | Yes | 8 in–1.7 ft | April to August | | Lemmon’s Milkweed | Asclepias lemmonii | Yes | 8 in–2 ft | July to September | | Slimpod Milkweed | Asclepias quinquedentata | Yes | 1 ft–2.5 ft | July to September | | Wheel Milkweed | Asclepias uncialis | Yes | 2 in–6 in | April to June | ## How to cite Milkweed USA. (2026). Milkweed in New Mexico. https://milkweedusa.com/states/new-mexico/ --- # Milkweed in Kansas > 24 milkweed species are recorded in Kansas. Source: https://milkweedusa.com/states/kansas/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Kansas is the crossroads of the central monarch flyway, and the Flint Hills hold the largest intact tallgrass prairie left on earth. Green antelopehorn, common, showy and Mead’s milkweed all occur, and fall migration through the state is spectacular. - Species recorded: 24 - USDA hardiness zones: 5a–7a - Monarch flyway: eastern - Best time to sow seed outdoors: October to November ## Species recorded in Kansas | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Antelope Horns | Asclepias asperula | Yes | 1 ft–2 ft | March to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Zizotes Milkweed | Asclepias oenotheroides | Yes | 8 in–2 ft | March to October | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Broadleaf Milkweed | Asclepias latifolia | Yes | 1 ft–3 ft | May to August | | Sand Milkweed | Asclepias arenaria | Yes | 1 ft–2.5 ft | June to August | | Plains Milkweed | Asclepias pumila | Yes | 4 in–1 ft | June to September | | Engelmann’s Milkweed | Asclepias engelmanniana | Yes | 2 ft–5 ft | June to August | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Poison Milkweed | Asclepias subverticillata | Yes | 1 ft–3 ft | June to September | | Dwarf Milkweed | Asclepias involucrata | Yes | 4 in–10 in | April to June | | Mead’s Milkweed | Asclepias meadii | Yes | 1 ft–2 ft | May to June | | Woolly Milkweed | Asclepias lanuginosa | Yes | 4 in–1 ft | May to June | | Wheel Milkweed | Asclepias uncialis | Yes | 2 in–6 in | April to June | ## How to cite Milkweed USA. (2026). Milkweed in Kansas. https://milkweedusa.com/states/kansas/ --- # Milkweed in Arkansas > 14 milkweed species are recorded in Arkansas. Source: https://milkweedusa.com/states/arkansas/ Licence: CC BY 4.0 (Milkweed USA) ## Overview The Ozark and Ouachita highlands give Arkansas dry glade species such as green antelopehorn and purple milkweed, while the Delta’s bottomland forests hold aquatic milkweed. Roadside and utility corridor management drives most monarch habitat in the state. - Species recorded: 14 - USDA hardiness zones: 6a–8b - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in Arkansas | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | ## How to cite Milkweed USA. (2026). Milkweed in Arkansas. https://milkweedusa.com/states/arkansas/ --- # Milkweed in Tennessee > 14 milkweed species are recorded in Tennessee. Source: https://milkweedusa.com/states/tennessee/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Tennessee runs from the Mississippi bottomlands to the Great Smoky Mountains, and its cedar glades in the Central Basin are a nationally important habitat holding green antelopehorn and green comet milkweed. White and fourleaf milkweed occupy the eastern woodlands. - Species recorded: 14 - USDA hardiness zones: 5b–8a - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in Tennessee | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | ## How to cite Milkweed USA. (2026). Milkweed in Tennessee. https://milkweedusa.com/states/tennessee/ --- # Milkweed in North Carolina > 19 milkweed species are recorded in North Carolina. Source: https://milkweedusa.com/states/north-carolina/ Licence: CC BY 4.0 (Milkweed USA) ## Overview North Carolina’s longleaf pine savannas hold specialist milkweeds, among them Carolina, largeflower, Michaux’s and fewflower, that occur almost nowhere else, while the mountains support poke and white milkweed. Prescribed fire is essential to keeping these coastal plain species alive. - Species recorded: 19 - USDA hardiness zones: 5b–8b - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in North Carolina | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Pinewoods Milkweed | Asclepias humistrata | Yes | 8 in–2 ft | March to June | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Tropical Milkweed | Asclepias curassavica | No | 2 ft–4 ft | nearly year-round in frost-free areas | | Carolina Milkweed | Asclepias cinerea | Yes | 1 ft–2.5 ft | May to August | | Michaux’s Milkweed | Asclepias michauxii | Yes | 8 in–1.7 ft | April to July | | Largeflower Milkweed | Asclepias connivens | Yes | 1 ft–2.5 ft | May to August | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | ## How to cite Milkweed USA. (2026). Milkweed in North Carolina. https://milkweedusa.com/states/north-carolina/ --- # Milkweed in South Carolina > 23 milkweed species are recorded in South Carolina. Source: https://milkweedusa.com/states/south-carolina/ Licence: CC BY 4.0 (Milkweed USA) ## Overview The Carolina sandhills and coastal plain savannas give South Carolina an unusual concentration of rare milkweeds, including Carolina, pinewoods, largeflower and velvetleaf milkweed. Most depend on regular burning of open pine woodland. - Species recorded: 23 - USDA hardiness zones: 7a–9a - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in South Carolina | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Pinewoods Milkweed | Asclepias humistrata | Yes | 8 in–2 ft | March to June | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Balloon Plant | Gomphocarpus physocarpus | No | 3 ft–6 ft | May to October | | Tropical Milkweed | Asclepias curassavica | No | 2 ft–4 ft | nearly year-round in frost-free areas | | Velvetleaf Milkweed | Asclepias tomentosa | Yes | 1 ft–2.5 ft | April to July | | Pineland Milkweed | Asclepias obovata | Yes | 1 ft–2.5 ft | June to August | | Carolina Milkweed | Asclepias cinerea | Yes | 1 ft–2.5 ft | May to August | | Michaux’s Milkweed | Asclepias michauxii | Yes | 8 in–1.7 ft | April to July | | Largeflower Milkweed | Asclepias connivens | Yes | 1 ft–2.5 ft | May to August | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | ## How to cite Milkweed USA. (2026). Milkweed in South Carolina. https://milkweedusa.com/states/south-carolina/ --- # Milkweed in District of Columbia > 9 milkweed species are recorded in District of Columbia. Source: https://milkweedusa.com/states/district-of-columbia/ Licence: CC BY 4.0 (Milkweed USA) ## Overview The District’s milkweed lives in Rock Creek Park, the Anacostia wetlands and a growing network of pollinator gardens on federal land. Common, swamp and butterfly milkweed all persist, and the city’s pollinator habitat commitments have added considerable planted acreage. - Species recorded: 9 - USDA hardiness zones: 7a–8a - Monarch flyway: eastern - Best time to sow seed outdoors: late October to early December ## Species recorded in District of Columbia | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | ## How to cite Milkweed USA. (2026). Milkweed in District of Columbia. https://milkweedusa.com/states/district-of-columbia/ --- # Milkweed in Texas > 35 milkweed species are recorded in Texas. Source: https://milkweedusa.com/states/texas/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Every monarch heading north from Mexico crosses Texas, which puts its spring-blooming milkweeds, antelope horns, green antelopehorn and zizotes, among the most consequential plants on the continent. The state also holds desert, Hill Country and coastal marsh species, more than thirty in total. - Species recorded: 35 - USDA hardiness zones: 6a–10a - Monarch flyway: both - Best time to sow seed outdoors: November to January ## Species recorded in Texas | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Antelope Horns | Asclepias asperula | Yes | 1 ft–2 ft | March to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Zizotes Milkweed | Asclepias oenotheroides | Yes | 8 in–2 ft | March to October | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Pineneedle Milkweed | Asclepias linaria | Yes | 1.5 ft–4 ft | March to October | | Texas Milkweed | Asclepias texana | Yes | 1 ft–3 ft | May to September | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Broadleaf Milkweed | Asclepias latifolia | Yes | 1 ft–3 ft | May to August | | Sand Milkweed | Asclepias arenaria | Yes | 1 ft–2.5 ft | June to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Balloon Plant | Gomphocarpus physocarpus | No | 3 ft–6 ft | May to October | | Tropical Milkweed | Asclepias curassavica | No | 2 ft–4 ft | nearly year-round in frost-free areas | | Plains Milkweed | Asclepias pumila | Yes | 4 in–1 ft | June to September | | Engelmann’s Milkweed | Asclepias engelmanniana | Yes | 2 ft–5 ft | June to August | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Pineland Milkweed | Asclepias obovata | Yes | 1 ft–2.5 ft | June to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Bract Milkweed | Asclepias brachystephana | Yes | 6 in–1.5 ft | April to August | | Giant Milkweed | Calotropis procera | No | 6 ft–12 ft | nearly year-round in frost-free areas | | Poison Milkweed | Asclepias subverticillata | Yes | 1 ft–3 ft | June to September | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | | Emory’s Milkweed | Asclepias emoryi | Yes | 4 in–1.2 ft | April to September | | Dwarf Milkweed | Asclepias involucrata | Yes | 4 in–10 in | April to June | | Longhood Milkweed | Asclepias macrotis | Yes | 8 in–1.7 ft | April to August | | Prostrate Milkweed | Asclepias prostrata | Yes | 2 in–6 in | March to September | | Sperry’s Milkweed | Asclepias sperryi | Yes | 8 in–1.7 ft | May to August | ## How to cite Milkweed USA. (2026). Milkweed in Texas. https://milkweedusa.com/states/texas/ --- # Milkweed in Oklahoma > 23 milkweed species are recorded in Oklahoma. Source: https://milkweedusa.com/states/oklahoma/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Oklahoma sits squarely in the central flyway funnel, with green antelopehorn and antelope horns on the prairies, sand milkweed in the dune country and swamp milkweed along the eastern rivers. The state is a spring and fall bottleneck for the whole eastern population. - Species recorded: 23 - USDA hardiness zones: 6a–8a - Monarch flyway: eastern - Best time to sow seed outdoors: October to November ## Species recorded in Oklahoma | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Showy Milkweed | Asclepias speciosa | Yes | 2 ft–5 ft | May to August | | Prairie Milkweed | Asclepias sullivantii | Yes | 2 ft–4 ft | June to July | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Antelope Horns | Asclepias asperula | Yes | 1 ft–2 ft | March to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Zizotes Milkweed | Asclepias oenotheroides | Yes | 8 in–2 ft | March to October | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Broadleaf Milkweed | Asclepias latifolia | Yes | 1 ft–3 ft | May to August | | Sand Milkweed | Asclepias arenaria | Yes | 1 ft–2.5 ft | June to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Plains Milkweed | Asclepias pumila | Yes | 4 in–1 ft | June to September | | Engelmann’s Milkweed | Asclepias engelmanniana | Yes | 2 ft–5 ft | June to August | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Poison Milkweed | Asclepias subverticillata | Yes | 1 ft–3 ft | June to September | | Dwarf Milkweed | Asclepias involucrata | Yes | 4 in–10 in | April to June | ## How to cite Milkweed USA. (2026). Milkweed in Oklahoma. https://milkweedusa.com/states/oklahoma/ --- # Milkweed in Louisiana > 19 milkweed species are recorded in Louisiana. Source: https://milkweedusa.com/states/louisiana/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Louisiana’s bottomland hardwood forests and cypress swamps support aquatic milkweed, one of the few species that grows in standing water and shade. The state is also a first landfall for monarchs crossing the Gulf, making fall nectar supply critical. - Species recorded: 19 - USDA hardiness zones: 8a–10a - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in Louisiana | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Pinewoods Milkweed | Asclepias humistrata | Yes | 8 in–2 ft | March to June | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Balloon Plant | Gomphocarpus physocarpus | No | 3 ft–6 ft | May to October | | Tropical Milkweed | Asclepias curassavica | No | 2 ft–4 ft | nearly year-round in frost-free areas | | Slimleaf Milkweed | Asclepias stenophylla | Yes | 1.5 ft–3.3 ft | June to August | | Pineland Milkweed | Asclepias obovata | Yes | 1 ft–2.5 ft | June to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | ## How to cite Milkweed USA. (2026). Milkweed in Louisiana. https://milkweedusa.com/states/louisiana/ --- # Milkweed in Mississippi > 20 milkweed species are recorded in Mississippi. Source: https://milkweedusa.com/states/mississippi/ Licence: CC BY 4.0 (Milkweed USA) ## Overview From the Delta to the Gulf coast, Mississippi holds aquatic, pinewoods and longleaf milkweed in wet savanna and sandhill habitats. The state’s remaining longleaf pine ecosystems are the stronghold for its rarer species. - Species recorded: 20 - USDA hardiness zones: 7b–9a - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in Mississippi | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Pinewoods Milkweed | Asclepias humistrata | Yes | 8 in–2 ft | March to June | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Balloon Plant | Gomphocarpus physocarpus | No | 3 ft–6 ft | May to October | | Tropical Milkweed | Asclepias curassavica | No | 2 ft–4 ft | nearly year-round in frost-free areas | | Pineland Milkweed | Asclepias obovata | Yes | 1 ft–2.5 ft | June to August | | Carolina Milkweed | Asclepias cinerea | Yes | 1 ft–2.5 ft | May to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | ## How to cite Milkweed USA. (2026). Milkweed in Mississippi. https://milkweedusa.com/states/mississippi/ --- # Milkweed in Alabama > 24 milkweed species are recorded in Alabama. Source: https://milkweedusa.com/states/alabama/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Alabama’s range from Appalachian foothills to Gulf coast gives it one of the richest milkweed floras in the Southeast, including pinewoods, Carolina, largeflower and aquatic milkweed. Fire-maintained longleaf pine habitat holds most of the rarities. - Species recorded: 24 - USDA hardiness zones: 7a–9a - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in Alabama | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Pinewoods Milkweed | Asclepias humistrata | Yes | 8 in–2 ft | March to June | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Balloon Plant | Gomphocarpus physocarpus | No | 3 ft–6 ft | May to October | | Tropical Milkweed | Asclepias curassavica | No | 2 ft–4 ft | nearly year-round in frost-free areas | | Velvetleaf Milkweed | Asclepias tomentosa | Yes | 1 ft–2.5 ft | April to July | | Pineland Milkweed | Asclepias obovata | Yes | 1 ft–2.5 ft | June to August | | Carolina Milkweed | Asclepias cinerea | Yes | 1 ft–2.5 ft | May to August | | Tall Green Milkweed | Asclepias hirtella | Yes | 2 ft–4 ft | June to August | | Michaux’s Milkweed | Asclepias michauxii | Yes | 8 in–1.7 ft | April to July | | Largeflower Milkweed | Asclepias connivens | Yes | 1 ft–2.5 ft | May to August | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | ## How to cite Milkweed USA. (2026). Milkweed in Alabama. https://milkweedusa.com/states/alabama/ --- # Milkweed in Georgia > 25 milkweed species are recorded in Georgia. Source: https://milkweedusa.com/states/georgia/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Georgia’s sandhills, coastal plain savannas and Piedmont woodlands support more than a dozen milkweed species, with pinewoods milkweed feeding the earliest spring monarchs moving north through the state. Prescribed burning drives the health of most of them. - Species recorded: 25 - USDA hardiness zones: 6a–9a - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in Georgia | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Purple Milkweed | Asclepias purpurascens | Yes | 2 ft–4 ft | May to July | | Poke Milkweed | Asclepias exaltata | Yes | 3 ft–6 ft | June to July | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Pinewoods Milkweed | Asclepias humistrata | Yes | 8 in–2 ft | March to June | | Common Milkweed | Asclepias syriaca | Yes | 3 ft–6 ft | June to August | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | Fourleaf Milkweed | Asclepias quadrifolia | Yes | 1 ft–2 ft | May to June | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Balloon Plant | Gomphocarpus physocarpus | No | 3 ft–6 ft | May to October | | Tropical Milkweed | Asclepias curassavica | No | 2 ft–4 ft | nearly year-round in frost-free areas | | Velvetleaf Milkweed | Asclepias tomentosa | Yes | 1 ft–2.5 ft | April to July | | Pineland Milkweed | Asclepias obovata | Yes | 1 ft–2.5 ft | June to August | | Carolina Milkweed | Asclepias cinerea | Yes | 1 ft–2.5 ft | May to August | | Michaux’s Milkweed | Asclepias michauxii | Yes | 8 in–1.7 ft | April to July | | Largeflower Milkweed | Asclepias connivens | Yes | 1 ft–2.5 ft | May to August | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | | Savannah Milkweed | Asclepias pedicellata | Yes | 6 in–1.5 ft | April to September | | Southern Milkweed | Asclepias viridula | Yes | 1 ft–2.5 ft | May to August | ## How to cite Milkweed USA. (2026). Milkweed in Georgia. https://milkweedusa.com/states/georgia/ --- # Milkweed in Hawaii > 3 milkweed species are recorded in Hawaii. Source: https://milkweedusa.com/states/hawaii/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Hawaii has no native milkweed. Monarchs arrived in the islands in the 1840s and now breed year-round on introduced tropical milkweed and balloon plant, forming a non-migratory resident population. Because they do not migrate, the usual advice about cutting back tropical milkweed does not apply in the same way here. - Species recorded: 3 - USDA hardiness zones: 9a–13a - Monarch flyway: none - Best time to sow seed outdoors: October to December, so the seed uses winter rain ## Species recorded in Hawaii | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Balloon Plant | Gomphocarpus physocarpus | No | 3 ft–6 ft | May to October | | Tropical Milkweed | Asclepias curassavica | No | 2 ft–4 ft | nearly year-round in frost-free areas | | Giant Milkweed | Calotropis procera | No | 6 ft–12 ft | nearly year-round in frost-free areas | ## How to cite Milkweed USA. (2026). Milkweed in Hawaii. https://milkweedusa.com/states/hawaii/ --- # Milkweed in Florida > 24 milkweed species are recorded in Florida. Source: https://milkweedusa.com/states/florida/ Licence: CC BY 4.0 (Milkweed USA) ## Overview Florida holds a resident non-migratory monarch population in the south alongside migrants passing through the panhandle, and its native flora includes aquatic, pinewoods, largeflower and velvetleaf milkweed. Tropical milkweed is the state’s biggest monarch conservation problem, because it never dies back and OE parasite loads build to damaging levels. - Species recorded: 24 - USDA hardiness zones: 8a–11a - Monarch flyway: eastern - Best time to sow seed outdoors: November to January ## Species recorded in Florida | Common name | Scientific name | Native | Height | Bloom | | --- | --- | --- | --- | --- | | Swamp Milkweed | Asclepias incarnata | Yes | 3 ft–5 ft | June to September | | Butterfly Weed | Asclepias tuberosa | Yes | 1 ft–3 ft | May to September | | Green Antelopehorn | Asclepias viridis | Yes | 1 ft–2.5 ft | April to July | | Aquatic Milkweed | Asclepias perennis | Yes | 1 ft–3 ft | May to September | | Pinewoods Milkweed | Asclepias humistrata | Yes | 8 in–2 ft | March to June | | Whorled Milkweed | Asclepias verticillata | Yes | 1 ft–2.5 ft | June to September | | Clasping Milkweed | Asclepias amplexicaulis | Yes | 1.5 ft–3 ft | May to July | | White Milkweed | Asclepias variegata | Yes | 1.5 ft–3.5 ft | May to July | | Fewflower Milkweed | Asclepias lanceolata | Yes | 2 ft–5 ft | May to August | | Green Comet Milkweed | Asclepias viridiflora | Yes | 1 ft–3 ft | May to August | | Red Milkweed | Asclepias rubra | Yes | 2 ft–4 ft | June to July | | Feay’s Milkweed | Asclepias feayi | Yes | 8 in–2 ft | April to September | | Balloon Plant | Gomphocarpus physocarpus | No | 3 ft–6 ft | May to October | | Tropical Milkweed | Asclepias curassavica | No | 2 ft–4 ft | nearly year-round in frost-free areas | | Velvetleaf Milkweed | Asclepias tomentosa | Yes | 1 ft–2.5 ft | April to July | | Pineland Milkweed | Asclepias obovata | Yes | 1 ft–2.5 ft | June to August | | Carolina Milkweed | Asclepias cinerea | Yes | 1 ft–2.5 ft | May to August | | Curtiss’ Milkweed | Asclepias curtissii | Yes | 1 ft–3 ft | April to September | | Giant Milkweed | Calotropis procera | No | 6 ft–12 ft | nearly year-round in frost-free areas | | Michaux’s Milkweed | Asclepias michauxii | Yes | 8 in–1.7 ft | April to July | | Largeflower Milkweed | Asclepias connivens | Yes | 1 ft–2.5 ft | May to August | | Longleaf Milkweed | Asclepias longifolia | Yes | 1 ft–2.5 ft | April to July | | Savannah Milkweed | Asclepias pedicellata | Yes | 6 in–1.5 ft | April to September | | Southern Milkweed | Asclepias viridula | Yes | 1 ft–2.5 ft | May to August | ## How to cite Milkweed USA. (2026). Milkweed in Florida. https://milkweedusa.com/states/florida/ --- # How to plant milkweed seeds > Milkweed seed is easy once you understand one thing: most species will not germinate until they think winter has happened. Everything else is detail. Source: https://milkweedusa.com/guides/how-to-plant-milkweed-seeds/ Licence: CC BY 4.0 (Milkweed USA) Milkweed seed has a built-in safety catch. In the wild the seed ripens in the fall, blows away on its parachute of floss, and lands somewhere that may or may not be a good place to grow. If it germinated straight away, the seedling would meet winter at two inches tall and die. So most species carry a dormancy that only a long cold, damp spell will break. Reproduce that spell and germination rates jump from around 20 percent to 80 or 90 percent. There are two ways to do it. > [tip] There is a printable version of this method, with a stratification table covering every species, at [milkweedusa.com/print](/print/). It is designed to live on a potting bench. ## Method one: cold-moist stratification in the fridge This is the reliable, controllable method, and the one to use if you want plants on a schedule. 1. Dampen a paper towel or a few tablespoons of clean sand or vermiculite. It should feel like a wrung-out cloth, never wet enough to drip. 2. Fold the seed into it, seal it in a zip-top bag, and label the bag with the species and the date. This matters more than you think, because unlabeled milkweed seed is indistinguishable between species. 3. Put it in the fridge, not the freezer. Around 4°C, or 40°F, is ideal. 4. Leave it for the number of days that species needs. Thirty days covers the great majority, 60 for the tougher western and montane species. 5. Sow immediately after chilling. Check the bag once a week. A little condensation is normal. Fuzzy gray mold means the medium was too wet; rinse the seed, use fresh, drier medium, and carry on. ## Method two: winter sowing outdoors Nature's own method, and by far the least work. Sow the seed into pots or into prepared ground in late fall or early winter and leave it outside. Cold and damp do the job for free, and seedlings appear when the soil warms in spring. The classic container version uses a translucent milk jug: cut it almost in half around the middle leaving a hinge, fill the base with four inches of compost, sow, tape it shut, remove the cap for ventilation and leave it outdoors somewhere it will get rain and snow. It is a miniature cold frame and it works extremely well. The trade-off is control. You cannot start winter sowing in March, and heavy rain, mice and squirrels all take their share. ## Sowing depth, light and temperature Sow shallowly. About 6 mm or a quarter of an inch of cover is right: enough to hold moisture, little enough that light still reaches the seed. Milkweed germination improves markedly with light, so seed buried an inch deep may simply sit there. After stratification, the seed wants warmth: 20 to 24°C, or 70 to 75°F. A warm windowsill is usually enough; a heat mat speeds things up. Keep the compost evenly moist, never sodden. Damping off is the main cause of losses at this stage. Most species emerge in one to three weeks. Aquatic milkweed and pinewoods milkweed, which are southern species with little or no dormancy, can be up in four days from fresh seed with no chilling at all. ## How long each species needs | Group | Species | Cold-moist stratification | | --- | --- | --- | | No chill needed | Tropical milkweed, aquatic milkweed, pinewoods milkweed | 0 days (sow fresh) | | Standard | Butterfly weed, common, showy, swamp, whorled, most prairie species | 30 days | | Long chill | Pallid, oval-leaf, woolly, wheel and Mead's milkweed | 60 days | > [tip] If you are unsure, 30 days never hurts. Over-stratifying is far less damaging than under-stratifying, and a few extra weeks in the fridge costs nothing. ## Scarification: usually unnecessary You will read advice to nick or sand the seed coat. For milkweed this is rarely needed and easy to get wrong. The exception is very old seed, four years or more, where a brief soak in warm water for 12 to 24 hours before stratifying can help. Do not use boiling water and do not soak longer than a day. ## Transplanting: the part people get wrong Milkweed roots divide into three types, and they behave completely differently. - **Taprooted species**, such as butterfly weed, purple milkweed, antelope horns, green antelopehorn and most desert species. These send a single deep root down fast. Pot them on early into deep containers, plant them out young, and accept that a mature plant essentially cannot be moved. Deep root-trainer cells or paper tubes are much better than shallow trays. - **Rhizomatous species**, such as common, showy, whorled and broadleaf milkweed. Tolerant of transplanting and inclined to spread once settled. - **Fibrous-rooted species**, such as swamp milkweed, aquatic milkweed and red milkweed. Easy to move, easy to divide, forgiving in every way. Plant out after your last frost date, water in well, and then be patient. First-year milkweed puts almost everything into roots. A butterfly weed that reaches six inches in its first summer is doing fine; it will be three feet across and covered in flower by year three. ## Direct sowing into the ground For meadows, prairie plantings or any project at scale, direct sowing in late fall is by far the cheapest route. Remove existing vegetation first, because milkweed seedlings lose badly to established grass. Broadcast onto bare soil, press the seed in with a roller or by walking on it, and do not cover deeply. Expect a low germination percentage and sow accordingly, at roughly ten times the density you want. ## What to expect in year one - Weeks 1–3: germination. - Weeks 4–8: two to four pairs of true leaves. Growth looks alarmingly slow. - Months 3–6: root development, minimal top growth. Do not feed, because rich soil produces floppy plants. - Year 2: real height, sometimes first flowers. - Year 3: full size and full bloom. Swamp milkweed and tropical milkweed often flower in their first year. Butterfly weed usually takes two, sometimes three. ## Questions **Do milkweed seeds need cold stratification?** Most species do. Thirty days of cold-moist stratification at about 4°C raises germination from roughly 20 percent to 80 percent or more. The exceptions are warm-climate species such as tropical, aquatic and pinewoods milkweed, which germinate readily from fresh seed with no chilling. **How long does milkweed take to germinate?** Seven to 21 days after stratification, at 20–24°C with light. Southern species sown fresh can emerge in as little as four days. **Can I just scatter milkweed seed on the ground?** Yes, if you scatter it in the fall onto bare soil so winter provides the stratification, and press it in rather than burying it. Scattering onto established grass in spring almost never works. **Why did my milkweed seeds not come up?** The three usual causes are missing or insufficient cold stratification, sowing too deep so light cannot reach the seed, and compost that was either bone dry or waterlogged. Old seed stored warm also loses viability quickly. ## References - Luna, T. and Dumroese, R. K. (2013). Monarchs (Danaus plexippus) and milkweeds (Asclepias species): the current situation and methods for propagating milkweeds. Native Plants Journal 14(1): 5–15. https://doi.org/10.3368/npj.14.1.5 - Borders, B. and Lee-Mäder, E. (2014). Milkweeds: A Conservation Practitioner’s Guide. The Xerces Society for Invertebrate Conservation, Portland, Oregon. https://xerces.org/publications/guidelines/milkweeds-conservation-practitioners-guide - USDA, NRCS (2026). The PLANTS Database. National Plant Data Team, Greensboro, North Carolina. https://plants.usda.gov/ ## How to cite Milkweed USA. (2026). How to plant milkweed seeds. https://milkweedusa.com/guides/how-to-plant-milkweed-seeds/ --- # When to plant milkweed > There are two good windows for milkweed and one bad one. Fall suits seed; late spring suits plants; midsummer suits almost nothing. Source: https://milkweedusa.com/guides/when-to-plant-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## The short answer **Sow seed in the fall.** Late October through December in most of the country, so winter does the stratification for you and the seed germinates on its own schedule in spring. **Plant potted plants and plugs in late spring**, after your last frost, or in early fall in the South where roots can establish through a mild winter. **Avoid planting anything in midsummer.** Milkweed transplanted in July has to build a root system in the worst possible conditions, and taprooted species rarely recover. ## Fall sowing, region by region | Region | Sow seed outdoors | Plant plugs | | --- | --- | --- | | Northeast & Upper Midwest | Late Oct – early Dec | Late May – June, or early Sept | | Mid-Atlantic & Ohio Valley | Nov – Dec | May, or Sept | | Southeast & Gulf Coast | Nov – Jan | Oct – Nov, or March | | Great Plains | Oct – Nov | May – early June | | Mountain West | Sept – Nov, before hard freeze | Late May – June | | Desert Southwest | Nov – Jan | Oct – Nov, or Feb – March | | Pacific Northwest | Oct – Nov | April – May | | California | Oct – Dec, to use winter rain | Nov – Jan | The principle behind the table is simple: sow when the seed will next experience a real cold, damp period, and plant when roots can grow without the top of the plant being cooked. ## Why fall beats spring for seed Fall sowing costs nothing, needs no fridge space, and produces stronger plants. Seed sown in November sits through winter, breaks dormancy naturally, and germinates in the first warm spell, often weeks before you could have got spring-sown seedlings into the ground. Those seedlings then have the whole growing season to build roots. The one real risk is a mild, wet winter that lets seed germinate in a January warm spell and then kills the seedlings in February. That is a genuine concern in the Southeast and along the Pacific Coast, which is why fridge stratification followed by a February or March sowing is a reasonable alternative there. ## Spring sowing: what to do if you missed fall Stratify in the fridge for 30 days and sow indoors six to eight weeks before your last frost. Grow the seedlings on under lights or on a bright windowsill, harden them off over a week, and plant out after the frost date. You will be about a month behind fall-sown plants by midsummer, and level with them by year two. ## Planting nursery plants Potted milkweed goes in best in late spring, once the soil has genuinely warmed. Points that matter: - Water in thoroughly, then water weekly for the first six weeks and stop. Established milkweed of most species wants far less water than gardeners give it. - Do not add compost or fertiliser to the planting hole for dry-country species. Butterfly weed in enriched soil grows soft and flops. - Plant at the same depth it was in the pot. Burying the crown invites rot. - Do not tease out the roots of taprooted species. Slide the plant in with the root ball intact. > [warn] Check that any nursery plant has not been treated with neonicotinoid insecticides. Systemic neonics persist in leaf tissue for months and will kill the caterpillars the plant was bought to feed. Ask directly, and buy from native plant nurseries who can answer the question. ## When milkweed emerges in spring This causes more panic than any other question. Milkweed is late. Butterfly weed in particular can be four to six weeks behind the rest of the border, and in cold regions it may not show until late May or even June. Mark every milkweed with a stake in the fall. More established plants are lost to spring digging and enthusiastic mulching than to any pest. ## Cutting back and fall management Leave the stems standing through winter if you can. They hold seed, shelter overwintering insects, and look good under frost. Cut them back in late winter, before new growth starts. The exception is tropical milkweed in zone 9 and warmer, which should be cut hard in October and kept cut through February to prevent winter monarch breeding and the parasite build-up that goes with it. ## Questions **What is the best month to plant milkweed seeds?** November in most of the United States. Fall sowing lets winter supply the cold stratification the seed needs, and germination happens naturally in early spring. If you have missed fall, stratify in the fridge for 30 days and sow indoors six to eight weeks before your last frost. **Can you plant milkweed in the summer?** Potted plants can go in during early summer if you water them consistently, but midsummer is the worst time for transplanting, especially for taprooted species like butterfly weed. Sowing seed in summer usually fails because the seed has had no cold period. **How late can you plant milkweed?** Seed can be sown outdoors any time before the ground freezes, and in mild regions right through winter. Potted plants should go in at least six weeks before your first hard frost so the roots can settle. ## References - Luna, T. and Dumroese, R. K. (2013). Monarchs (Danaus plexippus) and milkweeds (Asclepias species): the current situation and methods for propagating milkweeds. Native Plants Journal 14(1): 5–15. https://doi.org/10.3368/npj.14.1.5 - Borders, B. and Lee-Mäder, E. (2014). Milkweeds: A Conservation Practitioner’s Guide. The Xerces Society for Invertebrate Conservation, Portland, Oregon. https://xerces.org/publications/guidelines/milkweeds-conservation-practitioners-guide - Monarch Joint Venture (2026). Monarch conservation resources and monitoring protocols. Monarch Joint Venture, St Paul, Minnesota. https://monarchjointventure.org/ ## How to cite Milkweed USA. (2026). When to plant milkweed. https://milkweedusa.com/guides/when-to-plant-milkweed/ --- # Collecting and storing milkweed seed > Time the harvest wrong by a week and the seed either is not ripe or is halfway across the county. Here is how to get it right, and how to de-floss a pod in thirty seconds. Source: https://milkweedusa.com/guides/collecting-milkweed-seed/ Licence: CC BY 4.0 (Milkweed USA) ## Knowing when a pod is ready Milkweed pods ripen from late summer into fall, and the window between ripe and gone is short. The test that never fails: **squeeze the pod gently along its seam.** If it resists, it is not ready. If the seam splits open under light pressure and shows brown seed inside, harvest now. If it splits and the floss puffs out immediately, you are a day or two late, so collect what you can. Other signals: - The pod has gone from bright green to gray-green, tan or brown. - The seams look slightly swollen or have begun to show a pale line. - Seed inside is **brown**, not white or cream. White seed is immature and will not germinate, no matter how ripe the pod looks. Color of the pod alone is unreliable; some species stay green until the moment they open. Trust the seam squeeze and the seed color. ## Harvesting Cut or snap the pod off with an inch of stalk. Drop them into a paper bag, never plastic, which traps moisture and grows mold within a day. Label the bag by species and location as you go. If a pod is close but not quite there, harvest it anyway and put a rubber band or a twist tie around it. It will finish ripening in the bag and cannot burst open and lose its seed. > [note] Where you collect matters. Take no more than a fifth of the pods in any wild population, take nothing at all from rare species, and get permission before collecting on private land. Collecting is prohibited in national parks and on most public conservation land, and federally listed species such as Mead's milkweed may not be collected anywhere. ## Separating seed from floss The floss is the reason people give up. Three methods, in order of how well they work: **The coin-in-the-bag method.** Put the opened pods in a paper bag with a few coins or a couple of small stones. Shake hard for thirty seconds. The seed strips off and falls to the bottom while the floss stays clumped at the top. Lift out the floss and pour off the seed. This is the fastest method by a wide margin. **The strip method.** Hold an opened pod by the stem end, pinch the exposed brown seeds where they are still attached to the central core, and pull the whole seed mass off in one piece with the floss attached at the far end. Then run your thumb along the seeds and they drop free. This works beautifully on pods harvested at exactly the right moment. **The wet method.** Drop the whole seed-and-floss mass into a bucket of water. Floss floats, seed sinks. Skim the floss, pour off the water, and dry the seed thoroughly on newspaper for several days. Only use this if you can guarantee complete drying afterward. Do all of this indoors, away from any breeze, and preferably not over a carpet. ## Cleaning and drying Spread the seed in a single layer on a plate or newspaper for three to five days in a dry room. Blow gently across it to remove the last of the floss and any chaff. The seed should be dry enough to rattle. Discard anything white, thin, flat or noticeably light. Those seeds are unfertilised or immature and will not grow. ## Storing seed Milkweed seed stores well if kept **cool, dry and dark**. Paper envelopes or glass jars inside a sealed container in the refrigerator are ideal. Add a silica gel packet if you have one. - At room temperature: viable for roughly one to two years, declining fast. - Refrigerated and dry: three to five years with good germination. - Frozen and thoroughly dried: five years or more. Label every packet with species, date and collection site. Provenance matters: seed from a population 50 miles away is better adapted to your conditions than seed bought from three states over. ## Do you need to stratify seed you collected yourself? Yes, unless you sow it outdoors in the fall, in which case winter does it. Fresh seed carries the same dormancy as bought seed. The only real exceptions are the southern species, aquatic, pinewoods and tropical milkweed, which germinate readily from fresh seed with no chilling at all. ## A note on wild-collected versus bought seed Locally collected seed is genetically matched to your climate, costs nothing, and comes with a known origin. Bought seed is more convenient and legally straightforward, but check where it was grown. A butterfly weed from Florida stock planted in Minnesota may break dormancy at the wrong time and struggle. Look for suppliers who state the ecoregion or seed zone of their stock. ## Questions **When should I harvest milkweed pods?** When the seam splits under gentle pressure and the seeds inside are brown rather than white. This is usually September or October in the North and October to November in the South, but the squeeze test beats any calendar. **How do you get milkweed seeds out of the floss?** Put the opened pods in a paper bag with a few coins and shake for thirty seconds. The seed strips off and falls to the bottom, the floss stays clumped at the top. It is far quicker than picking seeds off by hand. **How long do milkweed seeds stay good?** One to two years at room temperature, three to five years stored dry in a refrigerator, and longer still if properly dried and frozen. Keep them cool, dry and dark and label them with the collection date. ## References - Borders, B. and Lee-Mäder, E. (2014). Milkweeds: A Conservation Practitioner’s Guide. The Xerces Society for Invertebrate Conservation, Portland, Oregon. https://xerces.org/publications/guidelines/milkweeds-conservation-practitioners-guide - Luna, T. and Dumroese, R. K. (2013). Monarchs (Danaus plexippus) and milkweeds (Asclepias species): the current situation and methods for propagating milkweeds. Native Plants Journal 14(1): 5–15. https://doi.org/10.3368/npj.14.1.5 - The Xerces Society (2026). Milkweed Seed Finder. Xerces Society for Invertebrate Conservation. https://xerces.org/milkweed-seed-finder ## How to cite Milkweed USA. (2026). Collecting and storing milkweed seed. https://milkweedusa.com/guides/collecting-milkweed-seed/ --- # Milkweed and monarch butterflies > A monarch caterpillar can eat milkweed and nothing else. Remove milkweed from a landscape and you remove monarchs from it. That is the whole conservation story in one sentence. Source: https://milkweedusa.com/monarchs/ Licence: CC BY 4.0 (Milkweed USA) ## An obligate relationship Monarchs (*Danaus plexippus*) are what ecologists call an obligate specialist: the larvae feed on plants in the milkweed subfamily and nothing else. Adults will drink nectar from almost any flower, but a female will only lay her eggs on milkweed, and a caterpillar offered anything else will starve rather than eat it. The reason is chemical. Milkweeds defend themselves with cardiac glycosides, or cardenolides, which disrupt the sodium-potassium pump in animal cells and are genuinely poisonous to most vertebrates. Monarchs carry mutations in that pump that make them insensitive, so they can eat the toxin, store it in their own tissue, and become poisonous themselves. The orange and black of an adult monarch advertises exactly that. Milkweed's defense became the monarch's defense. The relationship goes further. Milkweed also defends itself with latex, the white sap that gives the plant its name, which is sticky enough to glue a young caterpillar's mouthparts shut. Newly hatched monarch larvae respond by cutting a small circular trench in the leaf before feeding, which drains the latex pressure from the patch inside the circle. Watch a first-instar caterpillar closely and you will see it do this. ## How much milkweed does a garden need? More than most people plant. The rough figures: - One caterpillar eats roughly **20 to 25 large leaves** to reach pupation, which is most of one small plant. - A cluster of **at least 10 stems** is enough to raise a handful of caterpillars through to chrysalis. - Female monarchs find dense patches far more readily than isolated plants. Ten milkweeds in one bed will out-produce ten milkweeds scattered around a garden. - Plant **two or three species** with different bloom and leaf timings, so there is soft, edible foliage from May through September. If you have room for one species, plant swamp milkweed. If you have room for a patch, plant common milkweed in the East or showy milkweed in the West. If you have a border and want the plants to behave, use swamp milkweed, butterfly weed and purple milkweed together. ## Which milkweeds support the most caterpillars Leaf area and leaf softness matter most. Broad-leaved species carry more larvae per stem, and species that stay soft late in the season carry the important final generation. | Species | Region | Why it matters | | --- | --- | --- | | Common milkweed | East & Midwest | The single biggest contributor to eastern monarch production | | Showy milkweed | West & Plains | The western equivalent, along every irrigation ditch and riverbank | | Swamp milkweed | Nearly nationwide | Stays soft late, carries the final generation | | Narrowleaf milkweed | Pacific states | Backbone of western monarch recovery | | Green antelopehorn | South-central | Feeds the first northbound generation each spring | | Antelope horns | Texas & Southwest | In leaf in March when monarchs arrive from Mexico | | Prairie milkweed | Tallgrass prairie | Broad soft leaves, high larval survival | ## The season matters as much as the plant The eastern monarch migration works in relay. Butterflies that leave Mexico in March lay eggs in Texas and the Gulf states, and it is their children and grandchildren that reach the northern states by June. A fourth or fifth generation, born in late summer, makes the entire return flight to Mexico. That means two moments carry disproportionate weight: **March and April in Texas, Oklahoma and the Gulf states.** The migrating generation is old and running out of time. If antelope horns and green antelopehorn are not up and growing, the relay stumbles at the first step. **August and September everywhere.** The migratory generation needs nectar, not leaves, and vast quantities of it, to build the fat reserves for a 3,000 kilometer flight. Late-flowering natives such as goldenrod, blazing star, ironweed and asters are as important in the fall as milkweed is in spring. > [tip] Planting milkweed without planting late-season nectar is half a habitat. The single most useful fall addition to a monarch garden in most of the country is goldenrod. ## The western population Monarchs west of the Rockies overwinter in coastal California groves rather than in Mexico, and their numbers have fallen far more steeply than the eastern population, from millions in the 1980s to counts in the low tens of thousands in recent years. Narrowleaf and showy milkweed are the two species that matter most for western recovery. One important regional rule: **do not plant milkweed within about five miles of the California coast between Mendocino and Baja.** Overwintering monarchs need to stay in reproductive diapause, and milkweed near the groves encourages them to break it and breed in winter instead. Plant nectar plants there instead, and put milkweed inland. ## What else eats milkweed Monarchs are the famous one but the milkweed community is large, and most of it is harmless: milkweed tussock moth caterpillars (hairy, orange and black, gregarious), large and small milkweed bugs, red milkweed beetles, milkweed leaf beetles and swamp milkweed leaf beetles. Queen and soldier butterflies, both close monarch relatives, use the same host plants across the southern states. None of these need controlling. A milkweed patch stripped by tussock moths in August has already done its monarch work for the year and will return unharmed next spring. ## Rearing monarchs indoors: proceed carefully Bringing caterpillars inside is popular and it is not straightforwardly good. Research suggests indoor-reared monarchs can show impaired migratory orientation, and dense rearing spreads the OE parasite quickly. If you do rear: - Keep numbers small: a handful, not hundreds. - Sterilise containers between broods with a 20 percent bleach solution. - Rinse cut milkweed before feeding. - Release adults within a day of their wings hardening, near where the eggs were found. - Never move caterpillars or chrysalises between regions. Leaving eggs on the plant, and simply growing more plants, does more good than rearing. ## Questions **Do monarchs only eat milkweed?** Monarch caterpillars eat only milkweed and closely related plants in the Asclepiadoideae. Adult butterflies drink nectar from a wide range of flowers, but eggs are laid only on milkweed and larvae will starve rather than eat anything else. **How many milkweed plants do I need for monarchs?** At least ten stems in one place. A single caterpillar eats roughly 20 to 25 large leaves, and females locate dense patches far more easily than scattered plants. Two or three species with staggered bloom times is better than ten of one. **Will planting milkweed attract monarchs to my garden?** Usually yes, if you are within the breeding range and the patch is big enough to be found. It commonly takes a season or two, because plants need to reach a decent size before females start finding them reliably. **Should I bring monarch caterpillars indoors?** Generally no, or only a few. Indoor rearing at scale spreads the OE parasite and there is evidence it impairs migratory navigation. Growing more milkweed and leaving eggs where they were laid helps more. ## References - Agrawal, A. A. (2017). Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution. Princeton University Press. https://press.princeton.edu/books/hardcover/9780691166353/monarchs-and-milkweed - Pleasants, J. M. and Oberhauser, K. S. (2013). Milkweed loss in agricultural fields because of herbicide use: effect on the monarch butterfly population. Insect Conservation and Diversity 6(2): 135–144. https://doi.org/10.1111/j.1752-4598.2012.00196.x - Pleasants, J. M. (2017). Milkweed restoration in the Midwest for monarch butterfly recovery: estimates of milkweed stems needed. Insect Conservation and Diversity 10(1): 42–53. https://doi.org/10.1111/icad.12198 - Malcolm, S. B. (1994). Milkweeds, monarch butterflies and the ecological significance of cardenolides. Chemoecology 5/6: 101–117. https://doi.org/10.1007/BF01240595 - Zalucki, M. P. and Brower, L. P. (1992). Survival of first instar larvae of Danaus plexippus in relation to cardiac glycoside and latex content of Asclepias humistrata. Chemoecology 3: 81–93. https://doi.org/10.1007/BF01245886 - Monarch Joint Venture (2026). Monarch conservation resources and monitoring protocols. Monarch Joint Venture, St Paul, Minnesota. https://monarchjointventure.org/ ## How to cite Milkweed USA. (2026). Milkweed and monarch butterflies. https://milkweedusa.com/monarchs/ --- # The tropical milkweed problem > It is the most widely sold milkweed in America and, south of the frost line, the most damaging plant a monarch gardener can buy. Source: https://milkweedusa.com/guides/tropical-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## What tropical milkweed is *Asclepias curassavica* is a tropical American species, native from Mexico through South America and the Caribbean, but not native to the United States. It is easy to spot: red-orange petals with a bright yellow crown, and near-continuous flowering. Garden centers love it because it germinates without stratification, blooms in twelve weeks from seed, flowers all season, and looks spectacular in a pot. Monarchs love it because it is nutritious and always available. Both of those facts are the problem. ## Two documented harms **It keeps monarchs breeding through winter.** Native milkweeds die back with the first frost, and the disappearance of the host plant is one of the cues that pushes late-season monarchs into reproductive diapause and southward migration. In Florida, along the Gulf Coast, in southern California, Arizona and Hawaii, tropical milkweed never dies back. Monarchs encountering green, flowering milkweed in November behave as though it is still summer: they stay, and they breed. **It concentrates the OE parasite.** *Ophryocystis elektroscirrha* is a protozoan that infects monarchs. Spores from an infected female's abdomen fall onto the leaves she lays on; the caterpillar eats them; the parasite develops inside it. Infected adults emerge weak, sometimes unable to expand their wings, with shorter lifespans and reduced flight ability. Migration normally keeps OE in check. Heavily infected butterflies cannot complete a long flight, so they are removed from the population, and the plants they contaminated die back over winter. A perennial evergreen milkweed patch breaks both mechanisms. Spores accumulate on leaves that never die, and a resident non-migratory population passes them from generation to generation. Studies of resident populations on year-round tropical milkweed have found infection rates approaching 100 percent, against roughly 8 percent in the migratory eastern population. There is also evidence that cardenolide concentrations in tropical milkweed rise under high temperatures to levels that can harm the larvae feeding on it, a concern that increases as summers get hotter. ## Where it is genuinely a problem, and where it is not **Zones 9 to 11: Florida, the Gulf Coast, coastal and southern California, southern Arizona and Texas, Hawaii.** This is where the harm is real and documented. Do not plant it. **Zones 8 and below, most of the country.** Frost kills it every year, so it functions as an annual, dies back on schedule and cannot sustain winter breeding. The evidence of harm here is much weaker. It is still not a native plant, still supports fewer other insects than a native species, and there is still a better option for every situation. But a tropical milkweed in a Michigan garden is not causing a monarch crisis. ## If you already have it You do not have to rip it out today, but do one of these: 1. **Cut it back hard.** In zone 9 and warmer, cut every stem to within six inches of the ground in October, and keep cutting any regrowth through the end of February. This mimics the winter dieback the plants would otherwise never have. 2. **Replace it gradually.** Plant natives alongside it this season, and remove the tropical milkweed once they establish. 3. **Grow it in a pot** and move it into a shed or garage for the winter. > [warn] Cutting back matters most in exactly the places where it feels most wrong, on a plant covered in flowers and caterpillars in November. Those November caterpillars are the problem, not the reason to leave it standing. ## What to plant instead | If you garden in | Plant instead | | --- | --- | | Florida | Aquatic milkweed, pinewoods milkweed, butterfly weed | | Gulf Coast & Deep South | Aquatic milkweed, swamp milkweed, green antelopehorn | | Texas | Green antelopehorn, antelope horns, zizotes milkweed | | Southern California | Narrowleaf milkweed, California milkweed, showy milkweed | | Arizona & New Mexico | Rush milkweed, desert milkweed, pineneedle milkweed | | Hawaii | No native milkweed exists; see the note below | **Hawaii is a special case.** There is no native Hawaiian milkweed, and the resident monarch population there has never migrated. The standard advice does not translate directly, though OE remains a real concern and cutting plants back periodically still reduces spore loads. ## The policy picture Several California counties and municipalities have restricted the sale of tropical milkweed, and a growing number of native plant societies and retailers have stopped stocking it voluntarily. Legislation has been debated in Florida. Nothing is settled nationally, so for now the decision sits with individual gardeners and nurseries. If you buy plants, ask what species they are. "Milkweed" on a label almost always means *A. curassavica*, and the red-and-yellow flowers give it away instantly. ## Questions **Is tropical milkweed bad for monarchs?** In frost-free regions, yes. Because it never dies back it encourages monarchs to breed through winter instead of migrating, and OE parasite spores accumulate on leaves that are never shed. In cold-winter regions where frost kills it annually, the evidence of harm is far weaker. **When should I cut back tropical milkweed?** Cut it to within six inches of the ground in October and keep it cut through February if you garden in USDA zone 9 or warmer. That reproduces the winter dieback of native milkweeds and reduces parasite build-up. **Is tropical milkweed illegal?** Not nationally. Some California counties and municipalities restrict its sale, and many native plant nurseries have stopped stocking it voluntarily, but there is no federal ban. **What is OE in monarchs?** Ophryocystis elektroscirrha, a protozoan parasite. Spores on milkweed leaves are eaten by caterpillars, and infected adults emerge weakened, often with deformed wings and shortened lives. Infection rates are far higher in non-migratory populations breeding on year-round milkweed. ## References - Satterfield, D. A., Maerz, J. C. and Altizer, S. (2015). Loss of migratory behavior increases infection risk for a butterfly host. Proceedings of the Royal Society B 282: 20141734. https://doi.org/10.1098/rspb.2014.1734 - Altizer, S. M., Oberhauser, K. S. and Brower, L. P. (2000). Associations between host migration and the prevalence of a protozoan parasite in natural populations of adult monarch butterflies. Ecological Entomology 25(2): 125–139. https://doi.org/10.1046/j.1365-2311.2000.00246.x - Faldyn, M. J., Hunter, M. D. and Elderd, B. D. (2018). Climate change and an invasive, tropical milkweed: an ecological trap for monarch butterflies. Ecology 99(5): 1031–1038. https://doi.org/10.1002/ecy.2198 - Agrawal, A. A. (2017). Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution. Princeton University Press. https://press.princeton.edu/books/hardcover/9780691166353/monarchs-and-milkweed ## How to cite Milkweed USA. (2026). The tropical milkweed problem. https://milkweedusa.com/guides/tropical-milkweed/ --- # Milkweed pests and problems > Almost nothing you find on a milkweed needs killing. The bright orange aphids are the exception people ask about most, and even they rarely matter. Source: https://milkweedusa.com/guides/milkweed-pests/ Licence: CC BY 4.0 (Milkweed USA) You planted this to feed insects. A milkweed covered in insects is a milkweed doing its job, and almost everything you find on one can be left alone. **Do not spray anything.** Insecticidal soap, neem, pyrethrin and horticultural oil all kill monarch eggs and young caterpillars. So does a systemic neonicotinoid, for months afterward. No spray removes aphids and spares monarchs. ## Oleander aphids The bright yellow-orange aphids that coat milkweed stems are *Aphis nerii*, the oleander aphid. They are non-native, they reproduce asexually, and every one you see is female. They are the single most common milkweed question there is. **Do they harm the plant?** Rarely much. Heavy infestations can distort new growth, reduce flowering and coat leaves in sticky honeydew that grows sooty mold. Established plants shrug it off. Seedlings and containerised plants suffer more. **What to do, in order of preference:** 1. **Nothing.** Ladybird larvae, lacewing larvae, hoverfly larvae, parasitic wasps and soldier beetles all arrive within a couple of weeks and eat the colony. If you spray, you kill the predators too, and the aphids, which reproduce faster, come back stronger. 2. **A jet of water.** Knock them off with a hose. They rarely climb back up. Repeat every few days if you like. 3. **Squash them by hand.** Run gloved fingers up the stem. Check carefully for monarch eggs first. They are pale, ribbed and the size of a pinhead, usually on the underside of a leaf. 4. **Cut off the worst tip growth**, if a single shoot is smothered and has no eggs on it. > [warn] Never use insecticidal soap or neem on milkweed. Both kill monarch eggs and first-instar caterpillars on contact, and neem residues can disrupt larval development for days afterward. ## Milkweed bugs Large milkweed bugs (*Oncopeltus fasciatus*) and small milkweed bugs (*Lygaeus kalmii*) are orange and black seed feeders. They cluster on pods, pierce seeds and drink the contents. They do no harm to the plant. If you are collecting seed they are a genuine nuisance, in which case bag the pods early or pick the bugs off. Otherwise leave them: they are native, they are part of the community, and their aposematic coloring is one of the classic examples of Müllerian mimicry in North America. ## Milkweed tussock moth Fuzzy caterpillars in tufts of black, orange and white, feeding in a group, usually appearing in late summer. *Euchaetes egle* is native and eats milkweed for the same reason monarchs do. A tussock moth colony can strip a plant completely, which alarms people. By the time they appear, from August onward, the plant has usually finished supporting monarchs for the year, and it will return unharmed next spring. If you genuinely need the foliage for late monarch caterpillars, move the tussock moths to another plant rather than killing them. ## Beetles - **Red milkweed beetle** (*Tetraopes tetrophthalmus*): red with black spots and very long antennae. Larvae feed on roots, adults on leaves. Harmless at garden scale, and the specific name is a joke about its split eyes, through which the antennae pass. - **Swamp milkweed leaf beetle** (*Labidomera clivicollis*): rounded, orange and black, like a large ladybird. Chews leaves. Harmless. - **Japanese beetle**: non-native and worth removing by hand into soapy water if numbers are high. ## Real problems Only a few things genuinely damage milkweed. **Crown and root rot.** The commonest killer of garden milkweed, and always a drainage problem. Butterfly weed in clay that stays wet over winter will die. Plant dry-country species on a slope, in a raised bed, or in gritty soil, and stop watering established plants. **Damping off in seedlings.** Overwatered, poorly ventilated seed trays. Use fresh compost, water from below, give the seedlings air movement. **Aster yellows.** A phytoplasma disease causing distorted, greenish, stunted flowers. Uncommon and incurable. Remove and destroy affected plants. **Deer and rabbits.** Mostly avoid milkweed because of the latex, but young shoots are sometimes browsed in spring. Damage is usually cosmetic. ## The neonicotinoid problem The most serious threat to a garden milkweed is not an insect. Neonicotinoid insecticides are systemic: applied to soil or seed, they move into every part of the plant, including leaves, pollen and nectar, and persist for months to years. Milkweed grown with neonics kills the caterpillars that eat it. Nursery stock is often treated. Ask the question directly, "have these been treated with neonicotinoids?", and if nobody can tell you, buy elsewhere. Native plant nurseries and native plant society sales are the safest sources, and seed you grow yourself is safest of all. ## Questions **How do I get rid of aphids on milkweed?** Knock them off with a jet of water, or squash them by hand after checking for monarch eggs. Do not use insecticidal soap or neem, because both kill monarch eggs and caterpillars. In most gardens, ladybirds and lacewings clear the colony within a couple of weeks if you leave it alone. **What are the orange bugs on my milkweed?** Bright orange-yellow ones clustered on stems are oleander aphids. Larger orange-and-black ones on the seed pods are milkweed bugs. Neither seriously harms the plant, and milkweed bugs are native and harmless. **Should I kill milkweed tussock moth caterpillars?** No. They are native and part of the milkweed community. They appear late in the season when monarch use is mostly over, and although they can strip a plant, it returns unharmed the following year. **Can I spray my milkweed for pests?** No. Every effective insecticide, including organic options like neem and insecticidal soap, kills monarch eggs and young caterpillars. Water, fingers and patience are the only safe controls. ## References - Agrawal, A. A. (2017). Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution. Princeton University Press. https://press.princeton.edu/books/hardcover/9780691166353/monarchs-and-milkweed - Borders, B. and Lee-Mäder, E. (2014). Milkweeds: A Conservation Practitioner’s Guide. The Xerces Society for Invertebrate Conservation, Portland, Oregon. https://xerces.org/publications/guidelines/milkweeds-conservation-practitioners-guide ## How to cite Milkweed USA. (2026). Milkweed pests and problems. https://milkweedusa.com/guides/milkweed-pests/ --- # How to identify milkweed > Every milkweed shares one unmistakable flower structure. Learn to read it and the genus becomes obvious; after that, leaves and habitat do the rest. Source: https://milkweedusa.com/identify/ Licence: CC BY 4.0 (Milkweed USA) > [tip] This key is available as a [printable two-page field sheet](/print/milkweed-identification-key.pdf), sized for a pocket or a clipboard. ## Start with the flower Milkweed flowers are unlike anything else in the North American flora. Once you can see the structure, identification to genus takes a second. Each tiny flower has **two tiers**: - **Five petals below, bent sharply backward** away from the center. On most species they point down the flower stalk. - **Five hoods above**, forming a crown. In many species each hood contains a curved **horn** projecting inward over the center. Nothing else looks like this. The flowers are borne in **umbels**, clusters where every flower stalk radiates from a single point, like the spokes of an umbrella. An umbel of two-tiered flowers is a milkweed. ## Then check the sap Break a leaf. Almost every milkweed bleeds thick white latex within seconds. It is the fastest confirmation there is. The important exception is **butterfly weed** (*Asclepias tuberosa*), whose sap is clear or barely cloudy. If you have an orange-flowered milkweed with clear sap and alternate leaves, you have butterfly weed. > [warn] Milkweed latex irritates skin and is genuinely dangerous in the eyes. Wash your hands after handling plants and never rub your eyes in the field. ## Leaf arrangement narrows it fast Look at how leaves attach to the stem. This single character splits the genus into three workable groups. ## Leaf shape and texture Once you know the arrangement, shape does most of the remaining work: - **Thread-fine leaves** (1–3 mm wide): whorled milkweed, poison milkweed, plains milkweed, slimleaf milkweed. - **Narrow, willow-like**: swamp milkweed, narrowleaf milkweed, Engelmann's milkweed. - **Broad and oblong** with a pale midrib: common milkweed, prairie milkweed. - **Nearly circular**: broadleaf milkweed, pallid milkweed. - **Heart-shaped and clasping**: heartleaf milkweed in the West, clasping milkweed in the East. - **Effectively leafless**: rush milkweed and whitestem milkweed in the desert Southwest. Texture matters too. Common and showy milkweed are downy; prairie milkweed is completely smooth; California and woollypod milkweed are thickly white-woolly; clasping milkweed is waxy and hairless with wavy edges. ## Pods seal the identification From late summer, the follicles are diagnostic: - **Warty and covered in soft spines**: common milkweed. - **Woolly, with blunt bumps**: showy milkweed. - **Smooth and spindle-shaped**: swamp milkweed, butterfly weed, most narrow-leaved species. - **Smooth with a few short projections**: prairie milkweed. - **Curved and pointing upward**: antelope horns, which is where the name comes from. Inside, every species but one packs brown seeds overlapping like fish scales, each with a tuft of silky floss. The exception is aquatic milkweed, whose seeds have no floss at all. ## The lookalikes that catch people out **Dogbane** (*Apocynum cannabinum*) is the big one. It also has milky sap, opposite leaves and a similar habitat. The differences: | | Milkweed | Dogbane | | --- | --- | --- | | Flowers | Two-tiered, with hoods and horns | Small, simple, bell-shaped, greenish-white | | Stems | Usually green, unbranched below the flowers | Often reddish, branching repeatedly | | Pods | One short, fat follicle | Long, thin, paired, hanging like beans | | Leaves | Usually stalkless or nearly so | On distinct short stalks | **Butterfly bush**, **swamp milkweed lookalikes** in the Vernonia and Eupatorium groups, and young **pokeweed** are all occasionally mistaken for milkweed in leaf. Break a stem: no white latex, not a milkweed. Then check for the two-tiered flower. ## A four-step field routine 1. **Umbel of two-tiered flowers?** If yes, it is a milkweed. 2. **Milky sap?** Confirms it, unless the flowers are orange and the sap clear, in which case: butterfly weed. 3. **Leaf arrangement.** Opposite, alternate or whorled? This eliminates most of the genus. 4. **Leaf shape, flower color, habitat and state.** Cross-reference against the species list for your state and you will usually have one or two candidates. Every species page here carries the diagnostic characters, an illustration drawn from those characters, and a state-by-state range, so you can work from any direction: from the plant, from the place, or from the flower color. ## Questions **How do I know if a plant is milkweed?** Look for an umbel of flowers where each flower has five petals bent sharply backward and five hoods forming a crown above them. Then break a leaf: almost every milkweed bleeds thick white latex. That combination is unique to the genus. **What is the difference between milkweed and dogbane?** Both have milky sap and opposite leaves, but dogbane has small simple bell-shaped flowers rather than the two-tiered milkweed flower, reddish repeatedly branching stems, and long thin paired pods instead of one fat follicle. **Which milkweed does not have milky sap?** Butterfly weed, Asclepias tuberosa. Its sap is clear or only faintly cloudy, and it also has alternate rather than opposite leaves, giving two exceptions in one plant. ## References - Woodson, R. E. (1954). The North American species of Asclepias L.. Annals of the Missouri Botanical Garden 41(1): 1–211. https://www.jstor.org/stable/2394652 - Flora of North America Editorial Committee (eds.) (2026). Flora of North America North of Mexico. Oxford University Press, New York and Oxford. http://floranorthamerica.org/ - Royal Botanic Gardens, Kew (2026). Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. https://powo.science.kew.org/ ## How to cite Milkweed USA. (2026). How to identify milkweed. https://milkweedusa.com/identify/ --- # Milkweed lookalikes and how to tell them apart > Milky sap is not enough. Several unrelated plants bleed white, and two of the lookalikes actively kill monarch caterpillars. Source: https://milkweedusa.com/guides/milkweed-lookalikes/ Licence: CC BY 4.0 (Milkweed USA) ## Hemp dogbane *Apocynum cannabinum* is the plant most often mistaken for milkweed, and understandably: milky sap, opposite leaves, similar height, same ditches and field edges. Tell them apart by flower and pod. Dogbane's flowers are tiny, simple, greenish-white bells in a loose cluster, with no reflexed petals, no hoods and no horns. Its pods are long, slender and in pairs, hanging like thin green beans, quite unlike milkweed's single fat follicle. Its stems are usually reddish and branch repeatedly above the middle. Monarchs will not lay on it, and larvae cannot develop on it. ## Black and pale swallowwort *Vincetoxicum nigrum* and *V. rossicum* are invasive Eurasian vines in the same family as milkweed, spreading aggressively through the Northeast and Great Lakes. They are twining, with glossy opposite leaves and small dark purple or pale pinkish star-shaped flowers, and they produce slender milkweed-like pods with silky seed. They matter because they are an **ecological trap**. Female monarchs will lay eggs on swallowwort, because the chemical cues are close enough, and the larvae then die. Every egg laid on swallowwort is a monarch lost. If you find swallowwort, remove it. Dig out the crown, bag and bin the pods before they open, and do not compost it. Report infestations to your state invasive species program. ## Honeyvine milkweed *Cynanchum laeve* is a native twining vine, a genuine relative, with heart-shaped leaves and small white fragrant flowers. Monarchs do occasionally use it successfully, so it is not an ecological trap. It is, however, a vigorous climber that many gardeners treat as a weed. It is not a substitute for true *Asclepias*. ## Spurges Several *Euphorbia* species bleed white latex and are commonly mistaken for milkweed seedlings. The sap is far more caustic, the flowers are minute and structurally nothing like a milkweed's, and the leaves are usually much smaller. Spurge latex can cause severe skin and eye reactions, so treat it with more care than milkweed, not less. ## Butterfly bush *Buddleja davidii* is sold as a butterfly plant and is often assumed to help monarchs. It provides nectar to adults, but no butterfly's caterpillars can eat it, and it is invasive in the Pacific Northwest and parts of the Southeast. Planting butterfly bush instead of milkweed feeds adult butterflies while giving them nowhere to breed. ## Balloon plant and giant swan plant *Gomphocarpus physocarpus* and *G. fruticosus*, sold as balloon plant or hairy balls, are African relatives with inflated spiny pods. Monarchs can and do use them as hosts. They are not native, they behave much like tropical milkweed in frost-free areas, and the same winter-breeding caution applies. ## Quick reference | Plant | Milky sap | Flowers | Safe for monarch larvae? | | --- | --- | --- | --- | | True milkweed (*Asclepias*) | Yes (except butterfly weed) | Two-tiered with hoods | Yes | | Hemp dogbane | Yes | Small greenish bells | No, and not used | | Swallowwort | Yes | Small dark star-shaped | **No. Eggs laid, larvae die** | | Honeyvine milkweed | Yes | Small white, fragrant | Sometimes | | Spurge | Yes, caustic | Minute, cup-like | No | | Butterfly bush | No | Long lilac spikes | No, nectar only | ## Questions **Is swallowwort dangerous to monarchs?** Yes. Female monarchs lay eggs on black and pale swallowwort because the chemical cues resemble milkweed, but the larvae cannot survive on it. It functions as an ecological trap and should be removed wherever it is found. **Is dogbane the same as milkweed?** No. Hemp dogbane is a related plant with milky sap and opposite leaves, but its flowers are small simple bells rather than the two-tiered milkweed flower, and its pods are long, thin and paired. Monarchs cannot use it. ## References - Flora of North America Editorial Committee (eds.) (2026). Flora of North America North of Mexico. Oxford University Press, New York and Oxford. http://floranorthamerica.org/ - USDA, NRCS (2026). The PLANTS Database. National Plant Data Team, Greensboro, North Carolina. https://plants.usda.gov/ - Monarch Joint Venture (2026). Monarch conservation resources and monitoring protocols. Monarch Joint Venture, St Paul, Minnesota. https://monarchjointventure.org/ ## How to cite Milkweed USA. (2026). Milkweed lookalikes and how to tell them apart. https://milkweedusa.com/guides/milkweed-lookalikes/ --- # Is milkweed poisonous? > Milkweed is genuinely toxic, but the practical risk in a garden is low. The species that cause real harm are the narrow-leaved ones, and the usual route is contaminated hay. Source: https://milkweedusa.com/guides/is-milkweed-poisonous/ Licence: CC BY 4.0 (Milkweed USA) > [warn] This page is general information, not veterinary or medical advice. If you think an animal or a person has eaten milkweed, contact a vet or poison control immediately. In the US, the ASPCA Animal Poison Control Center is on 888-426-4435 and Poison Control on 1-800-222-1222. ## What makes milkweed toxic Milkweeds contain **cardiac glycosides**, or cardenolides, the same class of compound as digitalis from foxglove. They inhibit the sodium-potassium pump that cells use to maintain electrical balance, which in animals means disrupted heart rhythm. Some species additionally contain neurotoxic resinoids, and it is these, more than the cardenolides, that produce the tremors and seizures seen in severe livestock poisoning. Concentration varies enormously between species. As a general rule the **narrow-leaved and whorled species carry much higher concentrations by weight** than the broad-leaved ones. Whorled milkweed, poison milkweed and woollypod milkweed are among the most dangerous; butterfly weed is among the mildest. ## Dogs and cats Milkweed is toxic to dogs and cats, but poisoning is uncommon. Pets rarely eat it: the latex is bitter and irritating, and animals normally stop after one mouthful. Signs of ingestion include drooling, vomiting, diarrhoea, dilated pupils, weakness, tremors and, at higher doses, irregular heartbeat, collapse and seizures. Sap in the eye causes intense irritation and, rarely, corneal damage. If your dog eats milkweed, do not wait for symptoms. Call your vet or the ASPCA line with the species name if you know it and an estimate of how much was eaten. Prognosis is generally good with prompt treatment. Practically: if you have a dog that chews plants indiscriminately, put milkweed in a bed the dog does not use. Most households with dogs and milkweed have no incident at all. ## Horses Horses are the domestic animal most at risk, and the danger is disproportionately from **hay**, not pasture. Milkweed retains its toxicity when dried, and a horse that would never graze around a milkweed in a field will eat it without hesitation baled into hay. As little as 0.1 percent of body weight of whorled milkweed can be fatal, under a pound for an average horse. Signs include colic, muscle tremors, staggering, rapid or irregular heartbeat, difficulty breathing, seizures and death. This is an emergency; call a vet immediately. Prevention is the whole strategy: know your hay source, inspect hay for milkweed stems, and control whorled and poison milkweed on hay ground and in paddocks. This is the one context where removing milkweed is clearly the right decision. ## Cattle, sheep and goats Same story. Sheep are especially susceptible, and most historic poisonings involve animals on overgrazed range where the palatable plants are gone and milkweed is what remains. Well-managed pasture with adequate forage rarely produces cases, because livestock avoid milkweed by choice. ## People Milkweed should not be eaten. Cases of human poisoning are rare and almost always involve foraging errors or consumption of raw plant material. The everyday risk is contact, not ingestion: - **Sap in the eye** is the real hazard. It causes severe pain, swelling and blurred vision that can last days, and there are documented cases of temporary vision loss. Flush with water for 15 minutes and seek medical attention. - **Skin contact** causes irritation and, in sensitive people, a rash. - Wear gloves when cutting stems, wash your hands afterward, and keep your hands away from your face. Some milkweed species have a long history of use as food when correctly prepared, and various tribes used the fiber and the latex. None of that makes casual consumption safe, and identification errors, since dogbane is far more toxic and grows in the same places, make foraging a poor idea. ## Which species are riskiest | Risk | Species | | --- | --- | | Highest | Whorled milkweed, poison milkweed, woollypod milkweed, antelope horns, broadleaf milkweed | | Moderate | Common milkweed, showy milkweed, green antelopehorn | | Lower | Butterfly weed, swamp milkweed, aquatic milkweed | ## Should you plant milkweed if you have animals? For most households, yes. Dogs and cats rarely eat it, and the broad-leaved garden species are the milder ones. Choose swamp milkweed or butterfly weed, site them away from where a dog habitually chews, and you have effectively no risk. If you keep horses, sheep, cattle or goats, be deliberate: keep milkweed out of paddocks and hay ground entirely, especially the narrow-leaved species, and plant it in a fenced garden area instead. ## Questions **Is milkweed poisonous to dogs?** Yes, milkweed is toxic to dogs, though poisoning is uncommon because the bitter latex deters them after a mouthful. Symptoms include drooling, vomiting, weakness and, at higher doses, irregular heartbeat and seizures. Call your vet or the ASPCA Animal Poison Control Center on 888-426-4435 if ingestion is suspected. **Is milkweed poisonous to horses?** Yes, and horses are the animal most at risk. The usual route is contaminated hay, since milkweed stays toxic when dried. As little as 0.1 percent of body weight of whorled milkweed can be fatal. Keep milkweed out of hay ground and paddocks. **Is milkweed poisonous to touch?** The sap irritates skin and is genuinely dangerous in the eyes, where it can cause severe pain and temporary vision loss. Wear gloves when cutting stems and wash your hands afterward. Simply brushing past a plant is harmless. **Can you eat milkweed?** It should not be eaten. Milkweed contains cardiac glycosides, and it is easily confused with dogbane, which is considerably more toxic. Historic food uses involved specific species and careful preparation and do not make casual foraging safe. ## References - Burrows, G. E. and Tyrl, R. J. (2013). Toxic Plants of North America, 2nd edition. Wiley-Blackwell, Ames, Iowa. https://www.wiley.com/en-us/Toxic+Plants+of+North+America%2C+2nd+Edition-p-9780813820347 - Malcolm, S. B. (1994). Milkweeds, monarch butterflies and the ecological significance of cardenolides. Chemoecology 5/6: 101–117. https://doi.org/10.1007/BF01240595 - USDA, NRCS (2026). The PLANTS Database. National Plant Data Team, Greensboro, North Carolina. https://plants.usda.gov/ ## How to cite Milkweed USA. (2026). Is milkweed poisonous?. https://milkweedusa.com/guides/is-milkweed-poisonous/ --- # How milkweed pollination works > Milkweed does not shed loose pollen. It packages it into saddlebags that clip onto an insect leg like a piece of luggage, and it does this so awkwardly that fewer than one flower in a hundred sets seed. Source: https://milkweedusa.com/guides/milkweed-pollination/ Licence: CC BY 4.0 (Milkweed USA) Only two plant families on earth package their pollen into discrete units transferred whole between flowers: the orchids and the milkweeds. Everything odd about milkweed flowers follows from this. ## The pollinium Milkweed pollen is bound into two waxy sacs called **pollinia**, joined by a pair of translucent arms to a small dark clip called the **corpusculum**. The whole assembly, two sacs and a clip, is a **pollinarium**, and it looks like a tiny pair of saddlebags. The pollinaria sit hidden inside five vertical slots between the hoods of the flower. They are not exposed to the air and cannot be blown anywhere. Wind pollination is impossible. ## How transfer happens An insect lands on the flower for nectar. Milkweed flowers are slippery and the footing is poor, which is the point. As the insect scrabbles for grip, a leg slips into one of the narrow slots. The slot narrows downward and guides the leg into the corpusculum, which clips onto it like a bulldog clip. When the insect pulls its leg free, the whole pollinarium comes with it. It now walks around with pollen saddlebags attached to a foot or a claw. At the next flower the process reverses, but it has to be precise. The insect's leg must slip into a slot again, and the pollinium must be oriented correctly to be stripped off inside the **stigmatic chamber**. In the minutes after removal the connecting arms twist and dry, rotating the sacs into the right presentation angle, a mechanism called reflexion. Too early and the pollinia will not fit; too late and the insect has already visited. ## Why so few pods The mechanism is spectacularly inefficient. Field studies typically find that **1 to 2 percent of common milkweed flowers set fruit**. An umbel of 75 flowers commonly produces one pod, sometimes none, occasionally two. That is not a fault in your garden. A milkweed cluster covered in flowers that produces a single pod is behaving completely normally. Reasons for the low rate include: - The pollinium must be removed intact, which requires an insect strong enough to pull it free. - It must then be inserted into a correctly oriented slot on a **different** plant. - Milkweeds are largely self-incompatible, so pollen from the same plant, or from a clone of it, is rejected. - The plant aborts most fertilized ovaries anyway, since one pod is a large investment of resources. That last point matters for gardeners: a milkweed patch that spreads by rhizome is often a single clone, and a single clone cannot pollinate itself. If your plants flower heavily and never set seed, plant a second, genetically unrelated plant. ## Who does the work Pollinaria are heavy. Small insects cannot pull them off, and some die trying. You will occasionally find a small bee or fly dead in a milkweed flower with a leg trapped in a slot. The effective pollinators are large and strong: - **Bumble bees**, the most important group for most species. - **Honey bees**, which frequently walk around with pollinia clipped to their legs. - **Large wasps**, including paper wasps and thread-waisted wasps. - **Butterflies**, including monarchs, which pick up pollinia on their legs and proboscis. - **Hummingbird moths and sphinx moths**, particularly on night-scented and pale-flowered species. Monarchs are, satisfyingly, both the milkweed's principal herbivore and one of its pollinators. ## What this means practically - **Do not judge a milkweed by its pod count.** One or two pods from a large clump is a normal year. - **Plant more than one genetically distinct plant** if you want seed. Seed-grown plants are all genetically different; divisions and rhizome spread are not. - **Do not spray anything** that harms large bees and wasps, because they are the only insects that can do this job. - **Hand-pollinating milkweed is possible** but fiddly: remove a pollinarium with a fine needle or the tip of a pin and insert it into a stigmatic slot on another plant. Growers who need controlled crosses do this routinely; it is rarely worth it in a garden. ## Questions **Why does my milkweed have flowers but no pods?** That is normal. Only about 1 to 2 percent of milkweed flowers set fruit, because pollen travels in packets that must be clipped onto and off insect legs precisely. Milkweeds are also largely self-incompatible, so a patch that spread by rhizome from one plant cannot pollinate itself. Add a second, seed-grown plant. **What is a pollinium?** A waxy sac containing all the pollen from one milkweed anther. Two pollinia joined by arms to a clip form a pollinarium, which attaches to an insect leg and is carried whole to the next flower. Only orchids and milkweeds package pollen this way. **What pollinates milkweed?** Large, strong insects: bumble bees, honey bees, big wasps, butterflies including monarchs, and sphinx moths. Small insects cannot pull the pollen packets free, and occasionally get trapped trying. ## References - Wyatt, R. and Broyles, S. B. (1994). Ecology and evolution of reproduction in milkweeds. Annual Review of Ecology and Systematics 25: 423–441. https://doi.org/10.1146/annurev.es.25.110194.002231 - Kephart, S. R. (1983). The partitioning of pollinators among three species of Asclepias. Ecology 64(1): 120–133. https://doi.org/10.2307/1937334 - Agrawal, A. A. (2017). Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution. Princeton University Press. https://press.princeton.edu/books/hardcover/9780691166353/monarchs-and-milkweed ## How to cite Milkweed USA. (2026). How milkweed pollination works. https://milkweedusa.com/guides/milkweed-pollination/ --- # Creating a monarch waystation > A monarch garden is three things: enough milkweed to raise caterpillars, enough late nectar to fuel the migration, and no pesticides. Everything else is refinement. Source: https://milkweedusa.com/guides/monarch-waystation/ Licence: CC BY 4.0 (Milkweed USA) ## The specification A functioning monarch habitat needs: 1. **At least 10 milkweed stems**, ideally of two or more species, grouped together rather than scattered. 2. **At least four nectar species**, chosen so something is flowering from early spring to hard frost. 3. **Full sun**, six hours minimum. Monarchs are heliotherms and will not use a shaded garden. 4. **Shelter from wind**, from a hedge, fence or shrub group. 5. **No insecticides at all**, including organic ones, and no neonicotinoid-treated nursery stock. 6. **Reduced tidiness.** Leave stems standing over winter, leave leaf litter, and do not mow everything at once. That is the whole design brief. Roughly 100 square feet does it well, but a large container group on a balcony genuinely helps too. ## Choosing milkweed for your garden Match the species to the site rather than the other way round. | Situation | Best choices | | --- | --- | | Ordinary border, want good behavior | Swamp milkweed, butterfly weed, purple milkweed | | Dry, sunny, poor soil | Butterfly weed, whorled milkweed, showy milkweed | | Wet spot or rain garden | Swamp milkweed, aquatic milkweed, red milkweed | | Meadow or large area | Common milkweed (East), showy milkweed (West) | | Shade or woodland edge | Poke milkweed, fourleaf milkweed, white milkweed | | Containers | Swamp milkweed, butterfly weed, tropical milkweed as an annual in cold zones | Check the species page for whether a plant is rhizomatous before putting it in a small bed. Common milkweed in a 4-by-8 border is a decision you will regret. ## Nectar: the half people forget Milkweed feeds caterpillars. Adults need nectar, and the fall migratory generation needs enormous quantities of it to build the fat that fuels the flight to Mexico. A garden with milkweed and nothing flowering in September is doing half a job. **Spring:** golden alexanders, wild geranium, phlox, native willows, redbud. **Summer:** bee balm, purple coneflower, mountain mint, milkweeds themselves, liatris, coreopsis. **Fall, the critical window:** goldenrod, New England aster and other native asters, ironweed, Joe Pye weed, blazing star, frostweed in the South. Goldenrod is the single most valuable fall plant for monarchs across most of the country. It does not cause hay fever. That is ragweed, which flowers at the same time. Plant nectar species in **blocks of at least three**, not as single specimens. Butterflies find masses of color, not individuals. ## Layout that works - Put milkweed in **groups of five or more of one species**, in full sun, ideally where you can see it, since monitoring is half the pleasure. - Place taller nectar plants behind, shorter in front, but avoid a rigid border: monarchs use the vertical structure. - Leave some **bare, sunny soil** for ground-nesting native bees, which make up the majority of bee species. - Add a **damp patch or shallow dish of wet sand** for puddling. Butterflies drink from damp earth, not open water. - Include a few **flat basking stones** in the sun. ## What to stop doing - **Stop spraying.** All of it. Insecticidal soap and neem kill monarch eggs and caterpillars as efficiently as synthetic products. - **Stop cutting everything down in the fall.** Overwintering insects live in hollow stems and leaf litter. Cut in late winter instead. - **Stop mowing the whole area at once.** Mow in sections, weeks apart, so something is always in flower and larvae are not all destroyed together. - **Stop buying untreated-status-unknown plants.** Ask about neonicotinoids every time. ## Getting it certified Monarch Watch runs the original **Monarch Waystation** certification, which requires milkweed, nectar plants, sun, and sustainable management, and sends you a numbered sign. The Xerces Society runs **Bring Back the Pollinators** with a similar pledge. Neither is necessary to help monarchs, but both are good for persuading a neighbor, a school or a homeowners' association that the untidy patch is deliberate. ## Contributing data If you want your garden to count for more than itself, the useful projects are Journey North for migration sightings, the Monarch Larva Monitoring Project for weekly larval counts, and iNaturalist for milkweed distribution records. Milkweed occurrence data from gardeners genuinely improves the range maps that conservation planning depends on. ## Questions **What is a monarch waystation?** A garden or habitat patch that provides milkweed for monarch caterpillars, nectar plants for adults, sun and shelter, and is managed without insecticides. Monarch Watch certifies waystations and issues numbered signs, but the certification is optional. The habitat is the point. **How big does a monarch garden need to be?** About 100 square feet works well, with at least ten milkweed stems and four nectar species. Smaller gardens and even container groups still help, particularly in cities where any habitat is scarce. **What should I plant with milkweed for monarchs?** Late-season nectar above all: goldenrod, New England aster, ironweed, blazing star and Joe Pye weed, which fuel the fall migration. Add spring and summer nectar such as golden alexanders, bee balm and mountain mint so something flowers continuously. ## References - Monarch Watch (2026). Monarch Waystation Program and tagging data. University of Kansas, Lawrence, Kansas. https://monarchwatch.org/ - Monarch Joint Venture (2026). Monarch conservation resources and monitoring protocols. Monarch Joint Venture, St Paul, Minnesota. https://monarchjointventure.org/ - Borders, B. and Lee-Mäder, E. (2014). Milkweeds: A Conservation Practitioner’s Guide. The Xerces Society for Invertebrate Conservation, Portland, Oregon. https://xerces.org/publications/guidelines/milkweeds-conservation-practitioners-guide ## How to cite Milkweed USA. (2026). Creating a monarch waystation. https://milkweedusa.com/guides/monarch-waystation/ --- # Buying milkweed seeds and plants > The two things that matter when buying milkweed: is it native to your region, and has it been treated with systemic insecticide? Everything else is preference. Source: https://milkweedusa.com/guides/buying-milkweed/ Licence: CC BY 4.0 (Milkweed USA) ## The two questions to ask **"Is this species native to my state?"** Check the species page here, or your state's native plant society list. Native species support more insects, survive local winters, and break dormancy on the right schedule. **"Have these plants been treated with neonicotinoids?"** Neonicotinoid insecticides are systemic, moving into leaves, pollen and nectar and persisting for months or years. A neonic-treated milkweed kills the caterpillars it was bought to feed. If the seller cannot answer, buy elsewhere. ## Where to buy, best first **Native plant society sales.** Almost every state has one, sales are usually held in spring and fall, plants are regionally appropriate, untreated, and cheap. This is the best option in most of the country, and the volunteers running it will tell you exactly what grows where you live. **Specialist native plant nurseries.** They stock regional genotypes, can tell you the seed provenance, and do not use neonics. Many ship bare-root or plugs. **Prairie and restoration seed suppliers.** Best for quantity. They sell by ecoregion or seed zone, which is exactly the information you want. Buying seed by the ounce is dramatically cheaper than buying plants. **Seed swaps and local gardeners.** Free, locally adapted, and you can ask how the parent plant behaves. **Mainstream garden centers.** Convenient and usually the worst option: often tropical milkweed, often treated, rarely labeled by species. If it is your only choice, ask about neonics and check the label for a real botanical name. ## Understanding what you are buying **Seed** is cheapest and gives the widest species choice, but needs stratification and produces flowering plants in year two or three. Best for quantity and for taprooted species that hate transplanting. **Plugs**, small plants in deep narrow cells, are the sweet spot. Cheap, establish fast, and the deep cells suit milkweed root systems. **Potted plants** in one-gallon containers cost the most and give you flowers this year. Check that the root system has not spiralled at the bottom of the pot. **Bare root** is offered by some suppliers in early spring. It works well for rhizomatous species and is much cheaper to ship. ## Regional genotype: does it matter? Yes, more than people expect. A butterfly weed grown from Texas seed and planted in Minnesota may leaf out at the wrong time and lose to a late frost, and its dormancy requirements will not match the local winter. Look for suppliers who state a seed zone, an ecoregion, or at least a state of origin, and prefer stock from within a few hundred miles. ## Cost expectations | Format | Typical price | | --- | --- | | Seed packet (50–100 seeds) | 3–5 USD | | Seed by the ounce (bulk) | 15–60 USD depending on species | | Plug (deep cell) | 4–8 USD | | One-gallon potted plant | 12–25 USD | Rare and slow species such as purple milkweed, prairie milkweed and most western specialties cost more and sell out early. Order in winter. ## What to avoid - **Unlabelled "milkweed"** at a big-box store. It is almost always tropical milkweed. - **Tropical milkweed at all** if you garden in zone 9 or warmer. - **Wildflower mixes** containing milkweed. The milkweed content is usually negligible and the mix often includes non-native filler species. - **Wild-dug plants.** Digging milkweed from the wild rarely works because of the taproot, and it damages the population you were trying to help. - **Sellers who cannot name the species.** *Asclepias* alone is not a species name. > [tip] If you want a lot of milkweed cheaply, the answer is almost always fall-sown seed from a regional supplier, broadcast onto prepared bare soil. Ten dollars of seed can plant an area that would cost several hundred in plugs. ## Questions **Where can I buy milkweed plants near me?** Native plant society sales and specialist native plant nurseries are the best sources, offering regionally appropriate species, no neonicotinoid treatment and knowledgeable staff. Mainstream garden centers usually stock tropical milkweed and often cannot tell you whether it has been treated. **How do I know if milkweed has been treated with neonicotinoids?** Ask the seller directly. There is no way to tell by looking, and the residues persist in leaf tissue for months. If nobody can answer the question, assume it has been treated and buy from a native plant nursery instead. **Is it cheaper to grow milkweed from seed?** Far cheaper. A few dollars of seed can plant an area that would cost hundreds in plugs. The trade-off is time, because seed-grown plants usually flower in their second or third year, and most species need cold stratification first. ## References - The Xerces Society (2026). Milkweed Seed Finder. Xerces Society for Invertebrate Conservation. https://xerces.org/milkweed-seed-finder - Borders, B. and Lee-Mäder, E. (2014). Milkweeds: A Conservation Practitioner’s Guide. The Xerces Society for Invertebrate Conservation, Portland, Oregon. https://xerces.org/publications/guidelines/milkweeds-conservation-practitioners-guide - Luna, T. and Dumroese, R. K. (2013). Monarchs (Danaus plexippus) and milkweeds (Asclepias species): the current situation and methods for propagating milkweeds. Native Plants Journal 14(1): 5–15. https://doi.org/10.3368/npj.14.1.5 ## How to cite Milkweed USA. (2026). Buying milkweed seeds and plants. https://milkweedusa.com/guides/buying-milkweed/ --- # Growing milkweed in containers > Milkweed in a pot is entirely possible if you respect one thing: these are deep-rooted plants, and depth matters more than width. Source: https://milkweedusa.com/guides/growing-milkweed-in-containers/ Licence: CC BY 4.0 (Milkweed USA) ## Depth is the whole problem Most milkweeds send down a taproot fast. A butterfly weed seedling six weeks old may have a root eight inches long under two inches of top growth. Put that in a shallow pot and the root circles, the plant stalls, and it never thrives. **Minimum depth: 12 inches. Better: 14 to 18 inches.** Width matters much less. A tall narrow pot beats a wide shallow one every time. ## Best species for containers | Species | Why it works | | --- | --- | | Swamp milkweed | Fibrous roots, clump-forming, tolerates regular watering. The easiest container milkweed | | Butterfly weed | Compact and drought-tolerant, but needs a deep pot and gritty mix | | Whorled milkweed | Small, fine-textured, thrives on neglect | | Tropical milkweed | Excellent in pots, but only as an annual in zone 8 and colder | | Aquatic milkweed | Ideal for a pot standing in a saucer of water, in the Southeast | | Rush milkweed | Architectural and drought-proof in Southwest gardens | Avoid common milkweed and showy milkweed, whose rhizomes fill a pot and strangle themselves within two seasons. ## Compost and drainage Use a free-draining mix, not a moisture-retentive potting compost. A good general recipe is two parts peat-free multipurpose to one part horticultural grit or perlite. For butterfly weed and desert species, go to a fifty-fifty mix with grit. Drainage holes must be generous. Do not use a cache pot without emptying it, because waterlogged roots kill more container milkweed than anything else. Do not feed heavily. A single application of slow-release fertiliser in spring at half the recommended rate is plenty. Rich feeding produces soft, floppy, aphid-prone plants. ## Watering Container plants dry out much faster than ground plants, so the standard advice about drought tolerance does not fully apply. - Swamp and aquatic milkweed: keep consistently moist. - Butterfly weed, whorled, desert species: water thoroughly, then let the top two inches dry before watering again. - All species: reduce watering sharply once dormant. ## Overwintering Roots in a pot experience much colder temperatures than roots in the ground. As a rule, a containerised perennial survives winter about **two USDA zones less hardy** than its rated range, so a zone 5 plant in a pot needs zone 7 conditions. Options: 1. **Sink the pot** into a garden bed or a pile of leaves for the winter and lift it in spring. 2. **Move it to an unheated garage or shed** after the foliage dies back. Water lightly once a month so the roots do not desiccate completely. 3. **Group pots together** against a house wall and wrap the outsides with hessian or bubble wrap. 4. **Grow tropical milkweed as an annual** and start again from seed, which takes about twelve weeks to flower. Cut back dead top growth in late winter, not fall. ## Raising monarchs on a balcony It works, with realistic expectations. A group of three to five pots of swamp milkweed on a sunny balcony will attract monarchs in the breeding range, especially above the second or third floor where females are already flying at that height. - Group the pots so they read as a patch. - Add a nectar pot of pentas, zinnias, lantana or a native aster beside the milkweed. - Expect to need more plants than you think; a few caterpillars strip a potted milkweed in days. Keep a spare plant in reserve. - Do not spray anything, including on nearby ornamental plants. ## Questions **Can you grow milkweed in a pot?** Yes, provided the pot is at least 12 inches deep, because most milkweeds are taprooted and stall in shallow containers. Swamp milkweed is the easiest, and butterfly weed works well in a deep pot with a gritty mix. Avoid common and showy milkweed, whose rhizomes quickly fill a container. **How big a pot does milkweed need?** At least 12 inches deep, ideally 14 to 18. Depth matters far more than width because of the taproot. A tall narrow pot outperforms a wide shallow one. **Will milkweed survive winter in a pot?** Only if you protect it. Roots in containers experience temperatures roughly two hardiness zones colder than roots in the ground. Sink the pot in the garden, move it into an unheated garage, or group and insulate pots against a wall. ## References - Luna, T. and Dumroese, R. K. (2013). Monarchs (Danaus plexippus) and milkweeds (Asclepias species): the current situation and methods for propagating milkweeds. Native Plants Journal 14(1): 5–15. https://doi.org/10.3368/npj.14.1.5 - Borders, B. and Lee-Mäder, E. (2014). Milkweeds: A Conservation Practitioner’s Guide. The Xerces Society for Invertebrate Conservation, Portland, Oregon. https://xerces.org/publications/guidelines/milkweeds-conservation-practitioners-guide ## How to cite Milkweed USA. (2026). Growing milkweed in containers. https://milkweedusa.com/guides/growing-milkweed-in-containers/ --- # Everything else that lives on milkweed > Monarchs are the famous tenant, not the only one. Roughly a dozen insects in North America eat milkweed and almost nothing else, and most of them wear the same orange and black warning colors. Source: https://milkweedusa.com/guides/milkweed-community/ Licence: CC BY 4.0 (Milkweed USA) A milkweed is not a plant with a butterfly on it. It is a small, well-defended island supporting a community of specialists that have each independently solved the same chemical problem, plus a crowd of visitors that come only for the nectar and take nothing else. Learning to recognize them changes what a milkweed patch looks like. Most of what people reach for a spray bottle over turns out to be the point. ## The specialists These insects eat milkweed and very little else. Every one of them has evolved some tolerance of cardiac glycosides, and most advertise it in orange, red and black. | Insect | What it does | Where you find it | | --- | --- | --- | | **Monarch** (*Danaus plexippus*) | Larvae eat leaves; the famous one | Everywhere milkweed grows | | **Queen** (*Danaus gilippus*) | Close monarch relative, larvae on the same plants | Southern states, Texas to Florida | | **Soldier** (*Danaus eresimus*) | Third *Danaus*, less common | South Texas and south Florida | | **Milkweed tussock moth** (*Euchaetes egle*) | Gregarious tufted caterpillars, can strip a plant | Eastern and central states, late summer | | **Delicate cycnia** (*Cycnia tenera*) | Pale moth whose larvae eat milkweed and dogbane | Eastern North America | | **Large milkweed bug** (*Oncopeltus fasciatus*) | Pierces and drinks seeds inside the pod | Nationwide, clustered on pods | | **Small milkweed bug** (*Lygaeus kalmii*) | Seed feeder, also scavenges dead insects | Nationwide | | **Red milkweed beetle** (*Tetraopes tetrophthalmus*) | Adults eat leaves, larvae eat roots | East of the Rockies | | Other *Tetraopes* beetles | A dozen species, several tied to one milkweed | Mostly southwestern | | **Swamp milkweed leaf beetle** (*Labidomera clivicollis*) | Rounded orange-and-black leaf chewer | Eastern and central states | | **Milkweed stem weevil** (*Rhyssomatus lineaticollis*) | Larvae tunnel inside the stem | Eastern North America | | **Oleander aphid** (*Aphis nerii*) | Bright yellow-orange, all female, non-native | Nationwide, and unmissable | > [note] The oleander aphid is the odd one out. It is not native to North America, it reproduces without males, and every individual you see is a clone. It is also the single most common milkweed question there is. It rarely does real damage and predators clear it within a couple of weeks. ## Why so many of them are orange and black Stand in front of a milkweed in August and count the color schemes. The monarch, the queen, the tussock moth caterpillar, both milkweed bugs, the red milkweed beetle and the swamp milkweed leaf beetle are all some combination of orange, red and black. That is not coincidence and it is not shared ancestry. These are beetles, bugs, moths and butterflies, lineages separated by hundreds of millions of years. Each has arrived at the same advertisement independently, because it works: a bird that learns not to eat one orange-and-black insect on a milkweed avoids all of them. Biologists call this a Müllerian mimicry ring, where several genuinely defended species converge on a shared warning signal and reinforce each other's lesson. Every bird that learns from one member protects the rest. The viceroy butterfly, which looks like a monarch, was for a century the textbook case of the other kind of mimicry: a harmless species cheating by copying a defended one. That turned out to be wrong. Viceroys are unpalatable in their own right, and the relationship is mutual reinforcement rather than fraud. It is a good example of a textbook fact that quietly changed. ## The visitors Far more insects come for the nectar than for the leaves. Milkweed flowers are among the richest nectar sources in the North American flora, and because the pollen is packaged into parcels that only a strong insect can carry, the flowers select for size. - **Bumble bees** are the most important pollinators of most species, and the most frequently seen carrying pollinia clipped to their legs. - **Honey bees** work milkweed heavily, and beekeepers near a large stand notice it in the honey. - **Large wasps**, including paper wasps and thread-waisted wasps, are effective pollinators and also hunt caterpillars on the same plant. - **Sphinx moths and hummingbird moths** work pale and night-scented species at dusk. - **Butterflies** of many families nectar at milkweed: fritillaries, swallowtails, hairstreaks, skippers and the monarchs themselves. - **Hummingbirds** take nectar from the showier species, and are too large to be caught by the flower's mechanism. ## The predators A milkweed patch is a hunting ground, and this is the part most gardeners never notice. - **Crab spiders** sit motionless in the umbels, colored to match the flowers, and take bees. - **Ambush bugs** do the same job with a different body plan. - **Ladybird beetles and lacewing larvae** arrive within a fortnight of an aphid outbreak and are the reason spraying is counterproductive. - **Paper wasps** carry off monarch caterpillars, which is difficult to watch and entirely normal. - **Tachinid flies and braconid wasps** parasitize monarch larvae, laying eggs that develop inside the caterpillar. Monarch survival from egg to adult in the wild is commonly estimated in low single-digit percentages. Almost all of that loss is predation and parasitism, not milkweed shortage. Both matter, but only one of them is something a gardener can fix. ## Birds and mammals - **Goldfinches** line their nests with milkweed floss, and time their late nesting partly to the availability of it. Leaving pods standing into autumn is a small gift to them. - **Orioles and black-headed grosbeaks** eat overwintering monarchs in Mexico in enormous numbers, having evolved ways to handle the toxins: grosbeaks tolerate the cardenolides, orioles gut the butterflies and eat only the least toxic parts. - **Deer and rabbits** mostly avoid milkweed because of the latex, though young shoots are occasionally browsed in spring. - **Mice and voles** take seed from fallen pods over winter. ## What this means for a garden Almost nothing on a milkweed needs controlling. The tussock moths arrive in August, after monarchs have largely finished with the plant, and it comes back unharmed next spring. The milkweed bugs eat seed, which is a nuisance only if you are collecting it. The beetles chew leaves cosmetically. The aphids get eaten. The only genuinely damaging things are a drainage problem, which rots the crown, and an insecticide, which removes the entire community including the one you planted for. The pests guide has the detail. A milkweed covered in insects is a milkweed working. ## Questions **What are the orange and black bugs on my milkweed?** Most likely large or small milkweed bugs, which feed on the seeds inside the pods and do no harm to the plant. Bright yellow-orange clusters on the stems are oleander aphids instead. Both are normal and neither needs controlling. **What eats milkweed besides monarchs?** About a dozen insects in North America eat milkweed and almost nothing else: queen and soldier butterflies, the milkweed tussock moth, delicate cycnia, large and small milkweed bugs, red milkweed beetles, the swamp milkweed leaf beetle, the milkweed stem weevil and several aphids. Hundreds more species visit the flowers for nectar without eating the plant. **Why are so many milkweed insects orange and black?** They are all chemically defended by the same plant toxins, and they have independently converged on the same warning coloration. A predator that learns to avoid one of them avoids all of them, so each species benefits from the others advertising too. This is called a Müllerian mimicry ring. **Should I remove milkweed tussock moth caterpillars?** No. They are native, they arrive in late summer after monarch use is mostly over, and although a colony can strip a plant, it returns unharmed the following spring. If you need the foliage for late monarch larvae, move them to another plant rather than killing them. ## References - Agrawal, A. A. (2017). Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution. Princeton University Press. https://press.princeton.edu/books/hardcover/9780691166353/monarchs-and-milkweed - Malcolm, S. B. (1994). Milkweeds, monarch butterflies and the ecological significance of cardenolides. Chemoecology 5/6: 101–117. https://doi.org/10.1007/BF01240595 - Kephart, S. R. (1983). The partitioning of pollinators among three species of Asclepias. Ecology 64(1): 120–133. https://doi.org/10.2307/1937334 - Borders, B. and Lee-Mäder, E. (2014). Milkweeds: A Conservation Practitioner’s Guide. The Xerces Society for Invertebrate Conservation, Portland, Oregon. https://xerces.org/publications/guidelines/milkweeds-conservation-practitioners-guide ## How to cite Milkweed USA. (2026). Everything else that lives on milkweed. https://milkweedusa.com/guides/milkweed-community/