Green Antelopehorn
Asclepias viridis Walter
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.
Also called Green Milkweed, Spider Milkweed.
- Height
- 1 ft–2.5 ft
- Spread
- 1.5 ft–3 ft
- Flowers
- green, purple
- Bloom
- April to July
- Light
- Full sun
- Soil moisture
- Dry, Average
- USDA zones
- 5–9
- Leaves
- Alternate, oblong
- Sap
- Milky latex
- Roots
- Deep taproot, resents transplanting
- Stratification
- 30 days cold-moist
- Range
- 18 states
When it flowers
Green Antelopehorn blooms April to July, peaking in May and June.
How to identify it
- 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 and wildlife value
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 green antelopehorn
Tough, drought-proof and long-lived on lean soils. Direct-sow; the taproot dislikes transplanting. Goes dormant in high summer heat.
Seed needs about 30 days of cold-moist stratification. Deep taproot, resents transplanting. See how to plant milkweed seed for the full method.
Cautions
Toxic to livestock in quantity, though rarely eaten by choice. More on milkweed toxicity.
Where green antelopehorn grows
Recorded in 18 states: Alabama, Arkansas, Colorado, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Missouri, Mississippi, Nebraska, New Mexico, Oklahoma, South Carolina, Tennessee, Texas.
Distribution is generalized to state level. For county-level maps see USDA PLANTS and BONAP.
Frequently asked 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 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 94737-1. Royal Botanic Gardens, Kew. Accepted name, authorship and global distribution.
- GBIF 3170294. Global Biodiversity Information Facility. Aggregated occurrence records.
- iNaturalist 60946. 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). Green Antelopehorn (Asclepias viridis). Retrieved DATE, from https://milkweedusa.com/species/green-antelopehorn/
"Green Antelopehorn (Asclepias viridis)." Milkweed USA, 2026, https://milkweedusa.com/species/green-antelopehorn/. Accessed DATE.
Milkweed USA. "Green Antelopehorn (Asclepias viridis)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/species/green-antelopehorn/.
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title = {Green Antelopehorn (Asclepias viridis)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/species/green-antelopehorn/},
note = {Accessed DATE}
}