Rush Milkweed
Asclepias subulata Decne.
A leafless-looking fountain of blue-green pencil-thick stems topped with cream flowers, growing in the hottest, driest washes of the Sonoran and Mojave deserts. It looks like a sculpture and needs no water at all.
Also called Desert Milkweed, Ajamete.
- Height
- 2 ft–6 ft
- Spread
- 2 ft–4 ft
- Flowers
- cream, white
- Bloom
- nearly year-round in frost-free areas
- Light
- Full sun
- Soil moisture
- Dry
- USDA zones
- 8–11
- Leaves
- Opposite, threadlike
- Sap
- Milky latex
- Roots
- Deep taproot, resents transplanting
- Stratification
- 30 days cold-moist
- Range
- 4 states
When it flowers
Rush Milkweed blooms nearly year-round in frost-free areas, peaking in April and May and September and October.
How to identify it
- Effectively leafless, because the narrow leaves drop early and leave bundles of erect stems.
- Stems pale blue-green, rush-like, growing in a dense vase-shaped clump.
- Cream to white flowers in small clusters near the stem tips, almost year-round.
Ecology and wildlife value
A critical desert host and nectar source that remains available when everything else has dried up, supporting monarchs, queens and desert pollinators through the long dry season.
Growing rush milkweed
A superb xeriscape plant for Phoenix, Tucson, Palm Springs and Las Vegas gardens. Full sun, no supplemental water once established, no frost below about 20°F.
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 rush milkweed grows
Recorded in 4 states: Arizona, California, Nevada, Utah.
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 94672-1. Royal Botanic Gardens, Kew. Accepted name, authorship and global distribution.
- GBIF 3170301. Global Biodiversity Information Facility. Aggregated occurrence records.
- iNaturalist 62291. 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). Rush Milkweed (Asclepias subulata). Retrieved DATE, from https://milkweedusa.com/species/rush-milkweed/
"Rush Milkweed (Asclepias subulata)." Milkweed USA, 2026, https://milkweedusa.com/species/rush-milkweed/. Accessed DATE.
Milkweed USA. "Rush Milkweed (Asclepias subulata)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/species/rush-milkweed/.
@misc{milkweedusa_speciesrushmilkweed,
title = {Rush Milkweed (Asclepias subulata)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/species/rush-milkweed/},
note = {Accessed DATE}
}