Asclepias incarnata, the swamp milkweed, rose milkweed, rose milkflower, swamp silkweed, or white Indian hemp, is a herbaceous perennial plant species native to North America. It grows in damp through wet soils and also is cultivated as a garden plant for its flowers, which attract butterflies and other pollinators with nectar. Like most other milkweeds, it has latex containing toxic chemicals, a characteristic that repels insects and other herbivorous animals. Description Swamp milkweed is an upright, tall plant, growing from thick, fleshy, white roots. Typically, its stems are branched and the clump forming plants emerge in late spring after most other plants have begun growth for the year. The oppositely arranged leaves are long and wide and are narrow and lance-shaped, with the ends tapering to a sharp point. The plants bloom in early through mid-summer, producing small, fragrant, pink to mauve (sometimes white) colored flowers in rounded umbellate racemes. The flower color varies from darker shades of purple through soft, pinkish purple and a white flowering form exists as well. The actinomorphic flowers have five reflexed petals and an elevated central crown. After blooming, green follicles, approximately long, are produced that when ripe, split open. They then release light or dark brown, flat seeds that are attached to silver-white, silky hairs which catch the wind. This natural mechanism for seed dispersal is similar to that used by other milkweed species. Taxonomy , Kew's Plants of the World Online (POWO) accepts 2 infraspecies, each having numerous synonyms: The flower stalks and abaxial leaf surfaces of subspecies pulchra are abundantly pubescent, whereas those of the autonymous subspecies are nearly glabrous. Habitat Swamp milkweed prefers moisture retentive through damp soils in full sun or partial shade and is typically found growing wild near the edges of ponds, lakes, streams, and low areas—or along ditches. It is one of the best attractors of the monarch butterfly (Danaus plexippus), which feeds on the flowers and lays eggs on the plants. The emerging caterpillars feed on the leaves. The plants have specialized roots which function in heavy, wet soils. The scented, thick, white roots are in environments low in oxygen. Blooming occurs in mid- through late summer and after blooming long, relatively thin, rounded follicles are produced that grow uprightly. They split open in late summer through late fall, releasing seeds attached to silky hairs, which act as parachutes that carry the seeds in wind