Sperry’s Milkweed
Asclepias sperryi Woodson
A rare Trans-Pecos endemic of limestone ridges and rocky slopes in far west Texas, with thread-fine leaves and small cream flowers, known from very few localities.
- Height
- 8 in–1.7 ft
- Spread
- 8 in–1.5 ft
- Flowers
- cream, green
- Bloom
- May to August
- Light
- Full sun
- Soil moisture
- Dry
- USDA zones
- 7–9
- Leaves
- Opposite, threadlike
- Sap
- Milky latex
- Roots
- Deep taproot, resents transplanting
- Stratification
- 30 days cold-moist
- Range
- 1 state
When it flowers
Sperry’s Milkweed blooms May to August, peaking in June.
How to identify it
- Thread-fine opposite leaves on slender clustered stems.
- Small cream-green flowers in sparse terminal clusters.
- Limestone slopes and ridges in the Trans-Pecos.
Ecology and wildlife value
A narrow Texas endemic with little documented ecology and a small known range.
Growing sperry’s milkweed
Not in cultivation; leave wild plants undisturbed.
Seed needs about 30 days of cold-moist stratification. Deep taproot, resents transplanting. See how to plant milkweed seed for the full method.
Cautions
A rare Texas endemic. Photograph and report rather than collect. More on milkweed toxicity.
Where sperry’s milkweed grows
Recorded in 1 state: Texas.
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 21294-2. Royal Botanic Gardens, Kew. Accepted name, authorship and global distribution.
- GBIF 3170239. Global Biodiversity Information Facility. Aggregated occurrence records.
- iNaturalist 158759. 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). Sperry’s Milkweed (Asclepias sperryi). Retrieved DATE, from https://milkweedusa.com/species/sperrys-milkweed/
"Sperry’s Milkweed (Asclepias sperryi)." Milkweed USA, 2026, https://milkweedusa.com/species/sperrys-milkweed/. Accessed DATE.
Milkweed USA. "Sperry’s Milkweed (Asclepias sperryi)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/species/sperrys-milkweed/.
@misc{milkweedusa_speciessperrysmilkweed,
title = {Sperry’s Milkweed (Asclepias sperryi)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/species/sperrys-milkweed/},
note = {Accessed DATE}
}