Tall Green Milkweed
Asclepias hirtella (Pennell) Woodson
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.
Also called Prairie Milkweed.
- Height
- 2 ft–4 ft
- Spread
- 10 in–1.5 ft
- Flowers
- green, white
- Bloom
- June to August
- Light
- Full sun
- Soil moisture
- Dry, Average
- USDA zones
- 4–8
- Leaves
- Alternate, narrow
- Sap
- Milky latex
- Roots
- Deep taproot, resents transplanting
- Stratification
- 30 days cold-moist
- Range
- 18 states
When it flowers
Tall Green Milkweed blooms June to August, peaking in July.
How to identify it
- 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 and wildlife value
Used by monarchs and by a wide range of small prairie bees and wasps.
Growing tall green milkweed
Available from prairie seed suppliers; needs lean soil and full sun.
Seed needs about 30 days of cold-moist stratification. Deep taproot, resents transplanting. See how to plant milkweed seed for the full method.
Cautions
Standard milkweed cautions. More on milkweed toxicity.
Where tall green milkweed grows
Recorded in 18 states: Alabama, Arkansas, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Missouri, Mississippi, Nebraska, Ohio, Oklahoma, Tennessee, Texas, Wisconsin.
Distribution is generalized to state level. For county-level maps see USDA PLANTS and BONAP.
References and further reading
Names, ranges and conservation status here are drawn from the databases below. Where those disagree with a regional flora, trust the flora.
- Plants of the World Online 21200-2. Royal Botanic Gardens, Kew. Accepted name, authorship and global distribution.
- GBIF 3170338. Global Biodiversity Information Facility. Aggregated occurrence records.
- iNaturalist 127690. Community observations, photographs and phenology.
- Wikipedia. General-audience article on this species.
- BONAP county distribution map. Biota of North America Program. County-level range map.
- NatureServe Explorer. Conservation status ranks at global and state level.
- World Flora Online. Nomenclature and synonymy.
- Woodson, R. E. (1954). The North American species of Asclepias L.. Annals of the Missouri Botanical Garden 41(1): 1–211. The monograph the modern taxonomy of the genus still rests on. View
- Flora of North America Editorial Committee (eds.) (2026). Flora of North America North of Mexico. Oxford University Press, New York and Oxford. Accepted names, keys and descriptions for the North American flora. View
- Royal Botanic Gardens, Kew (2026). Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Nomenclature and global distribution, keyed to IPNI name identifiers. View
- Kartesz, J. T. (Biota of North America Program) (2026). North American Plant Atlas. BONAP, Chapel Hill, North Carolina. County-level distribution maps, the basis for the ranges generalized here. View
- USDA, NRCS (2026). The PLANTS Database. National Plant Data Team, Greensboro, North Carolina. State-level distribution, wetland status and nomenclature. View
- Agrawal, A. A. (2017). Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution. Princeton University Press. The standard general account of the milkweed and monarch relationship. View
Cite this page
This page is licensed CC BY 4.0. Quote it, adapt it and reuse it, including commercially, as long as you credit Milkweed USA and link back.
Milkweed USA. (2026). Tall Green Milkweed (Asclepias hirtella). Retrieved DATE, from https://milkweedusa.com/species/tall-green-milkweed/
"Tall Green Milkweed (Asclepias hirtella)." Milkweed USA, 2026, https://milkweedusa.com/species/tall-green-milkweed/. Accessed DATE.
Milkweed USA. "Tall Green Milkweed (Asclepias hirtella)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/species/tall-green-milkweed/.
@misc{milkweedusa_speciestallgreenmilkweed,
title = {Tall Green Milkweed (Asclepias hirtella)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/species/tall-green-milkweed/},
note = {Accessed DATE}
}