Heartleaf Milkweed
Asclepias cordifolia (Benth.) Jeps.
Arguably the handsomest milkweed in the West: smooth, waxy, blue-gray heart-shaped leaves clasping arching purple stems, hung with clusters of dark wine-red flowers. A Sierra Nevada and Cascade foothill specialty.
Also called Purple Milkweed.
- Height
- 1 ft–3 ft
- Spread
- 1.5 ft–2.5 ft
- Flowers
- maroon, purple
- Bloom
- May to July
- Light
- Full sun, Part shade
- Soil moisture
- Dry
- USDA zones
- 6–9
- Leaves
- Opposite, cordate
- Sap
- Milky latex
- Roots
- Rhizomatous, spreads by root
- Stratification
- 30 days cold-moist
- Range
- 3 states
When it flowers
Heartleaf Milkweed blooms May to July, peaking in May and June.
How to identify it
- Leaves distinctly heart-shaped, clasping the stem, smooth and blue-glaucous.
- Stems often flushed purple and arching.
- Flowers deep red-purple with paler hoods, in loose nodding clusters.
- Rocky slopes and open conifer forest, 1,000 to 6,500 feet.
Unfamiliar words are in the glossary, and the identification key will narrow a plant down from what you can see.
The parts that identify it
Ecology and wildlife value
A key early host for western monarchs moving into the Sierra foothills, and one of the earliest western milkweeds to leaf out.
Monarchs are not the only thing that will find it. Expect large milkweed bugs on ripening pods, oleander aphids on the stems, red milkweed beetles at the flowers and, in late summer, milkweed tussock moths. Everything that lives on milkweed.
Growing heartleaf milkweed
Outstanding foliage plant for a dry mountain garden. Needs excellent drainage, some afternoon shade at low elevation, and no summer water.
Seed needs about 30 days of cold-moist stratification. Rhizomatous, spreads by root. See how to plant milkweed seed for the full method.
Cautions
Standard milkweed cautions. More on milkweed toxicity.
Where heartleaf milkweed grows
Recorded in 3 states: California, Nevada, Oregon.
County records from USDA PLANTS, public domain. Cross-check against BONAP and your regional flora before making management decisions.
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 21169-2. Royal Botanic Gardens, Kew. Accepted name, authorship and global distribution.
- GBIF 3170280. Global Biodiversity Information Facility. Aggregated occurrence records.
- iNaturalist 62248. 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
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Milkweed USA. (2026). Heartleaf Milkweed (Asclepias cordifolia). Retrieved DATE, from https://milkweedusa.com/species/heartleaf-milkweed/
"Heartleaf Milkweed (Asclepias cordifolia)." Milkweed USA, 2026, https://milkweedusa.com/species/heartleaf-milkweed/. Accessed DATE.
Milkweed USA. "Heartleaf Milkweed (Asclepias cordifolia)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/species/heartleaf-milkweed/.
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title = {Heartleaf Milkweed (Asclepias cordifolia)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/species/heartleaf-milkweed/},
note = {Accessed DATE}
}