Tufted Milkweed
Asclepias nummularia Torr.
One of the smallest milkweeds in North America, a low tuft of tiny round woolly leaves on rocky Arizona desert slopes, easy to walk past even in flower.
Also called Roundleaf Milkweed.
- Height
- 2 in–8 in
- Spread
- 6 in–1.2 ft
- Flowers
- cream, green
- Bloom
- April to August
- Light
- Full sun
- Soil moisture
- Dry
- USDA zones
- 7–10
- Leaves
- Opposite, orbicular
- Sap
- Milky latex
- Roots
- Deep taproot, resents transplanting
- Stratification
- 30 days cold-moist
- Range
- 1 state
When it flowers
Tufted Milkweed blooms April to August, peaking in May.
How to identify it
- Tiny, nearly circular, densely hairy leaves.
- Whole plant usually under six inches tall.
- Rocky slopes and desert grassland in central and southern Arizona.
Ecology and wildlife value
A poorly documented Sonoran Desert specialist of limited but real value to desert pollinators.
Growing tufted milkweed
Not in cultivation.
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 tufted milkweed grows
Recorded in 1 state: Arizona.
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 94488-1. Royal Botanic Gardens, Kew. Accepted name, authorship and global distribution.
- GBIF 3170341. Global Biodiversity Information Facility. Aggregated occurrence records.
- iNaturalist 158751. Community observations, photographs and phenology.
- 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). Tufted Milkweed (Asclepias nummularia). Retrieved DATE, from https://milkweedusa.com/species/tufted-milkweed/
"Tufted Milkweed (Asclepias nummularia)." Milkweed USA, 2026, https://milkweedusa.com/species/tufted-milkweed/. Accessed DATE.
Milkweed USA. "Tufted Milkweed (Asclepias nummularia)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/species/tufted-milkweed/.
@misc{milkweedusa_speciestuftedmilkweed,
title = {Tufted Milkweed (Asclepias nummularia)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/species/tufted-milkweed/},
note = {Accessed DATE}
}