Whorled Milkweed
(Asclepias verticillata)
Left: Asclepias verticillata (whorled milkweed) in ASMSA Garden in Summer 2024.
Above: Blooming Asclepias verticillata (whorled milkweed) with its fall flowers.
Plant Characteristics
Plant Preference/Growing Conditions:
Whorled milkweed prefers to be planted in well drained, infertile soil, and blooms best in full sunlight. It blooms later than others in the Milkweed family, with its flowers often blooming into September.
Growth Habit/Description:
Medium sized, upright growing, perennial with stems that grow from 12'-24' in. Stems produce 3-6 needle-like leaves per node, and small white flower clusters. Colonies of whorled milkweed attract more pollinators (self pollination is impossible), so it is best to plant in groups. Both male and female plants produce flowers.
Bloom Season:
Small, white flower clusters are produced in late summer through early fall, primarily June through September.
Fall and/or Winter Interest?
Yes. Leaves often turn yellow or orange later in the season, and optimal flower blooming happens in early fall (September). Leaves go dormant during the winter season, but do not die.
Distribution
Habitat: Whorled milkweed is found most commonly in central and eastern America. It can be found growing naturally at many different sites, including dry prairies, slopes, fields, open woods, and roadsides.
Native to Arkansas? Yes
Native to Garland County? Yes
Endemic to Arkansas? No
Ecological Value
Host Plant for Caterpillars?
Yes. Whorled Milkweed serves as a host for Monarch (Danaus plexippus) caterpillars and larvae.
Other Known Ecological Value?
Yes. Whorled Milkweed, like other milkweed plants, are essential for the survival of Monarch caterpillars and butterflies
Other Interesting Facts
Origin of Name: Named after it's leaves, which seem to be "whorled" on each node, and the milky sap it produces.
Toxicity: Every part of the Whorled Milkweed is extremely toxic during periods of rapid growth, and can cause severe effects for humans and animals if consumed.
Additional Names: Also sometimes referred to as Horsetail milkweed.
References
“Asclepias Verticillata (Whorled Milkweed).” Missouri Wildflowers Nursery, mowildflowers.net/asclepias-verticillata-whorled-milkweed-/. Accessed 16 Sept. 2024.
“Got Milkweed?” The Huntington, huntington.org/verso/got-milkweed#:~:text=Most%20milkweeds%20go%20dormant%20from,rejuvenated%20them%2C%20they%20will%20resprout. Accessed 16 Sept. 2024.
“Whorled Milkweed, Asclepias Verticillata.” American Meadows, www.americanmeadows.com/product/perennials/whorled-milkweed. Accessed 16 Sept. 2024.
“Whorled Milkweed.” Asclepias Verticillata | Prairie Nursery, www.prairienursery.com/whorled-milkweed-asclepias-verticillata.html. Accessed 16 Sept. 2024.
“Whorled Milkweed.” Mt. Cuba Center, 22 Nov. 2023, mtcubacenter.org/plants/whorled-milkweed/#:~:text=Whorled%20milkweed%20prefers%20full%20sun%20and%20handles%20dry%2C%20infertile%20soil%20well.
Last edited by Nora Medlock, September 2024.