Milkweed in Illinois
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.
The best milkweed to plant in Illinois
Native to the state, garden-worthy and useful to monarchs. Start here if you are planting rather than identifying.
All milkweed species in Illinois
| Species | Height | Flower | Bloom | Soil | Monarch |
|---|---|---|---|---|---|
| Swamp Milkweed Asclepias incarnata |
3 ft–5 ft | pink, rose, white | June to September | Wet / Average | |
| Butterfly Weed Asclepias tuberosa |
1 ft–3 ft | orange, yellow, red | May to September | Dry / Average | |
| Prairie Milkweed Asclepias sullivantii |
2 ft–4 ft | pink, rose | June to July | Average / Wet | |
| Purple Milkweed Asclepias purpurascens |
2 ft–4 ft | purple, magenta | May to July | Average / Dry | |
| Poke Milkweed Asclepias exaltata |
3 ft–6 ft | white, green | June to July | Average | |
| Green Antelopehorn Asclepias viridis |
1 ft–2.5 ft | green, purple | April to July | Dry / Average | |
| Aquatic Milkweed Asclepias perennis |
1 ft–3 ft | white, pink | May to September | Wet | |
| Common Milkweed Asclepias syriaca |
3 ft–6 ft | pink, mauve, white | June to August | Dry / Average | |
| Whorled Milkweed Asclepias verticillata |
1 ft–2.5 ft | white, green | June to September | Dry / Average | |
| Clasping Milkweed Asclepias amplexicaulis |
1.5 ft–3 ft | pink, green, mauve | May to July | Dry | |
| Fourleaf Milkweed Asclepias quadrifolia |
1 ft–2 ft | pink, white | May to June | Dry / Average | |
| White Milkweed Asclepias variegata |
1.5 ft–3.5 ft | white | May to July | Dry / Average | |
| Oval-leaf Milkweed Asclepias ovalifolia |
8 in–1.7 ft | white, green | June to July | Dry / Average | |
| Green Comet Milkweed Asclepias viridiflora |
1 ft–3 ft | green | May to August | Dry | |
| Tall Green Milkweed Asclepias hirtella |
2 ft–4 ft | green, white | June to August | Dry / Average | |
| Mead’s Milkweed Asclepias meadii |
1 ft–2 ft | green, cream | May to June | Average / Dry | |
| Woolly Milkweed Asclepias lanuginosa |
4 in–1 ft | cream, green | May to June | Dry |
Rare or protected in part of this range: Mead’s Milkweed, Woolly Milkweed. Do not collect seed or plants from wild populations of these species.
Planting milkweed in Illinois
Sow seed outdoors in late October to early December. Winter then supplies the cold-moist stratification most milkweed seed needs, and germination happens naturally as the soil warms. If you have missed that window, chill seed in the refrigerator for 30 days and sow after your last frost. The full method is here.
Illinois spans USDA zones 5a–7a, so check the zone range on each species page before committing. Match the species to your site rather than the other way round: dry, sunny and poor suits butterfly weed and the whorled species; a damp spot suits swamp milkweed; shade suits very few milkweeds at all.
Plant at least ten stems in one group rather than scattering them, because female monarchs find dense patches far more readily. Add late-season nectar such as goldenrod and asters so the fall migratory generation has fuel as well as host plants. How to lay out a monarch garden.
Where to buy milkweed in Illinois
Start with Illinois Native Plant Society. State native plant societies run the plant sales worth going to: locally grown, untreated stock, at a few dollars a plant, sold by people who can tell you where to put it.
Elsewhere in the midwest
One of the widest milkweed seed and bare-root ranges anywhere, with germination codes listed for every species.
Long-established independent nursery specializing in Midwestern natives.
Independent nursery growing Missouri-provenance natives.
Independent prairie seed and plant nursery in north-east Iowa.
Independent grower supplying Midwestern restoration projects.
Independent seed supplier with a broad milkweed range in small packets.
Independent Upper Midwest native seed producer.
Family-run Ozarks native seed producer.
Ships to you
Independent seed producer supplying restoration-scale native seed by the pound.
Family-run native seed producer for the eastern and central states.
Family-run Texas seed house focused on regional ecotypes.
Small independent mail-order nursery for eastern natives.
Ships plants from a network of independent native growers, so you can buy small quantities from wholesale nurseries.
These favor independent nurseries and non-profits over chain garden centers, which mostly stock unlabeled tropical milkweed and often cannot tell you whether it has been treated with neonicotinoids. Search the full directory by ZIP code.
Milkweed in Illinois: common questions
What milkweed is native to Illinois?
17 milkweed species are recorded in Illinois, including Swamp Milkweed (Asclepias incarnata), Butterfly Weed (Asclepias tuberosa), Prairie Milkweed (Asclepias sullivantii), Purple Milkweed (Asclepias purpurascens). The full list is on this page.
What is the best milkweed to plant in Illinois?
Swamp Milkweed, Butterfly Weed, Prairie Milkweed are the best combination of native, available and garden-worthy for Illinois. Swamp Milkweed is the easiest to start with.
When should I plant milkweed seed in Illinois?
Sow outdoors in late October to early December, so winter provides the cold stratification the seed needs. If you have missed that window, stratify seed in the refrigerator for 30 days and sow in spring after the last frost.
Does milkweed grow wild in Illinois?
Yes. 17 species occur in Illinois, typically on roadsides, field margins, prairie remnants and along watercourses. Almost all of Illinois’ original tallgrass prairie is now cropland, so its milkweed survives in railroad rights of way, cemetery prairies and roadside ditches.
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Milkweed USA. (2026). Milkweed in Illinois. Retrieved DATE, from https://milkweedusa.com/states/illinois/
"Milkweed in Illinois." Milkweed USA, 2026, https://milkweedusa.com/states/illinois/. Accessed DATE.
Milkweed USA. "Milkweed in Illinois." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/states/illinois/.
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author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/states/illinois/},
note = {Accessed DATE}
}