Giant Milkweed
Calotropis procera (Aiton) W.T. Aiton
A large shrub or small tree from Africa and Asia, naturalised in the warmest parts of the United States. Its huge blue-gray leaves and waxy purple-tipped white flowers make it a striking plant, and monarchs and queens use it as a host, but it is invasive on disturbed dry ground.
Also called Rooster Tree, Sodom Apple, Calotrope.
- Height
- 6 ft–12 ft
- Spread
- 4 ft–8 ft
- Flowers
- white, purple
- Bloom
- nearly year-round in frost-free areas
- Light
- Full sun
- Soil moisture
- Dry
- USDA zones
- 9–11
- Leaves
- Opposite, ovate
- Sap
- Milky latex
- Roots
- Deep taproot, resents transplanting
- Stratification
- None needed
- Range
- 5 states
When it flowers
Giant Milkweed blooms nearly year-round in frost-free areas, peaking in March and April and October.
How to identify it
- Shrub or small tree to twelve feet, far larger than any native milkweed.
- Very large, thick, blue-gray leaves clasping stout woody stems.
- Waxy white flowers with five purple-tipped lobes, in dense clusters.
- Sap is copious, thick and strongly irritant.
Ecology and wildlife value
Used by monarch and queen larvae in Florida, Hawaii and south Texas. It colonizes overgrazed and disturbed dry ground aggressively and is treated as invasive in parts of its introduced range.
Growing giant milkweed
Not recommended for planting in the United States. Where it is already present, monarchs will use it, but it displaces native vegetation and its sap is a serious hazard.
Seed needs no cold stratification and can be sown fresh. Deep taproot, resents transplanting. See how to plant milkweed seed for the full method.
Cautions
Non-native and invasive on dry disturbed ground. The latex is a severe skin and eye irritant, considerably more so than native milkweeds, and the whole plant is toxic. Wear eye protection if cutting it. More on milkweed toxicity.
Where giant milkweed grows
Recorded in 5 states: Arizona, California, Florida, Hawaii, Texas.
Distribution is generalized to state level. For county-level maps see USDA PLANTS and BONAP.
Frequently asked questions
Can monarchs eat giant milkweed?
Yes, monarch and queen larvae develop on Calotropis procera, and it is a common host in Florida, Hawaii and south Texas. It is not native to the United States, is invasive on disturbed dry land, and its sap is a much stronger irritant than any native milkweed.
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 1004515-2. Royal Botanic Gardens, Kew. Accepted name, authorship and global distribution.
- GBIF 5414566. Global Biodiversity Information Facility. Aggregated occurrence records.
- iNaturalist 120917. Community observations, photographs and phenology.
- Wikipedia. General-audience article on this species.
- 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). Giant Milkweed (Calotropis procera). Retrieved DATE, from https://milkweedusa.com/species/giant-milkweed/
"Giant Milkweed (Calotropis procera)." Milkweed USA, 2026, https://milkweedusa.com/species/giant-milkweed/. Accessed DATE.
Milkweed USA. "Giant Milkweed (Calotropis procera)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/species/giant-milkweed/.
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title = {Giant Milkweed (Calotropis procera)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/species/giant-milkweed/},
note = {Accessed DATE}
}