Asclepias tuberosa, commonly known as butterfly weed, is a species of milkweed native to eastern and southwestern North America.

[4] It is uncertain if reddish flowers are due to soil mineral content, ecotype genetic differentiation, or both.

[4] The plant looks similar to the lanceolate milkweed (Asclepias lanceolata), but is uniquely identified by the larger number of flowers, and the hairy stems that are not milky when broken.

[3][12] Because of its rough leaves and trichomes, it is not a preferred host plant of the monarch butterfly but caterpillars can be reared on it successfully.

[13][14][15] Further, it is one of the very lowest Asclepias species in cardenolide content, making it a poor source of protection from bird predation and parasite virulence and perhaps contributing to its lack of attractiveness to egg-laying monarchs.

[17] The seeds do not require stratification and can be immediately planted, though in commercial growing they are generally moist stratified at 5 °C for 30–60 days because this increases the germination rate.

[23] Use of the plant is contraindicated in pregnancy, during lactation or with infants due to its toxins, which include resinoids and pregnanes.