Common milkweed

Asclepias syriaca, commonly called common milkweed, butterfly flower, silkweed, silky swallow-wort, and Virginia silkweed, is a species of flowering plant. It is in the genus Asclepias, the milkweeds. This species is native to most of North America east of the Rocky Mountains, excluding the drier parts of the Prairies. It grows in sandy soils and sunny areas. It was one of the earliest North American species described in Cornut's 1635 work Canadensium Plantarum Historia. The specific name was reused by Linnaeus due to Cornut's confusion with a species from Asia Minor.

Common milkweed is a perennial herb growing to 1–2 m tall from a rhizome. The stem and all parts of the plants produce a white latex when broken. The leaves are opposite, simple broad ovate-lanceolate, 7–25 cm long and 3–12 cm broad, usually with an undulate margin and a red-colored main vein. They have very short petioles and velvety undersides.

The fragrant flowers are grouped in several spherical umbels. The individual flowers are 1–2 cm in diameter with five cornate hoods. The seeds have long, white, flossy hairs and are encased in large follicles.