Asclepias tuberosa is a perennial herb, to 70 cm tall, hairy, simple to branched above; stems emerging from a the crown of a stout tap root in May, living up to 25 years, not flowering before about 6 years, 1-few stems per plant, no vegetative reproduction (Klemow and Raynal 1986; Wyatt 1980).Sap clear
Leaves alternate below, opposite on branches, narrowly lance-shaped, to 10 cm long.
Flowers orange, ca 1 cm, in umbels, radially symmetrical, 5-parted, petals bent downward, stamens fused around style into a central column that is sheathed by a ring of fused scales (hoods), each scale bears a small horn on its internal surface, the entire central structure called the corona, a signature structure of Asclepiadaceae; mostly self-infertile, insect pollinated by bees and butterflies (Wilbur 1976), June-July.
Fruit dry, hollow pod, ca 10 cm, thin, erect, seeds brown, flat, numerous, with silky tufts, wind dispersed, Sept.-Oct..
Wetland status: UPL.
Frequency in NYC: Infrequent.
Habitat: Open, undisturbed, upland areas. Often planted in restorations of meadows and grasslands (Idlewild).
Notes: Dormant below ground Oct.-May. Seedlings eaten by rabbits; insect herbivores mostly Hemiptera (true bugs), (Wilbur 1976).