# 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/