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Swamp Milkweed Asclepias incarnata


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Swamp Milkweed
credit: Jennifer Anderson @ USDA-NRCS PLANTS Database

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Family: Asclepiadaceae, Milkweed view all from this family

Description Native herbaceous perennial. Upright, 3 to 5 feet tall, with 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. Leaves opposite, 2.75 to 6 inches long, narrow and lance-shaped.

Flowers: small, fragrant, pink to mauve (sometimes white) in rounded umbels. The flower color may vary from darker shades of purple to soft, pinkish purple and a white flowering form exists as well. The flowers have five reflexed petals and an elevated central crown. After blooming, green seed pods, approximately 12 centimeters (4.5 inches) long, are produced that when ripe, split open.

Warning All plants in the genus Asclepias are probably somewhat toxic, some fatally so, to both humans and animals. The sap of some causes skin irritation in humans. Sensitivity to a toxin varies with a personís age, weight, physical condition, and individual susceptibility. Children are most vulnerable because of their curiosity and small size. Toxicity can vary in a plant according to season, the plantís different parts, and its stage of growth; and plants can absorb toxic substances, such as herbicides, pesticides, and pollutants from the water, air, and soil.

Flower Early to mid-summer.

Flower June - August

Habitat Damp soils in full sun to partial shade; at edges of ponds, lakes, streams, low areas, and ditches.

Range Found throughout North America, except Washington, Oregon, California, and Alabama.

Discussion This plant is a wetland indicator. Other common names: rose milkweed, pink milkweed.

Comments Swamp milkweed can adapt to slightly drier sites. It thrives on sun and neglect.

Exposure Preference Sun to partial sun.

Native Distribution Nova Scotia to Manitoba & Utah (also Carbon County, Montana), s. to Florida, Mississippi & New Mexico

Site Preference Low, moist open woods & prairies; ditches; stream banks

Soil Preference Rich, wet soils.

Wildlife Value Milkweeds are an important food source for the monarch caterpillar.