The Medicinal Plant Garden

of Birmingham-Southern College

  • Asclepias incarnata
  • Asclepias incarnata
  • Asclepias incarnata
  • Asclepias incarnata

Common Name

Swamp Milkweed, Pleurisy Root

Geographic Distribution and Habitat

Swamp milkweed is widely distributed across the U.S. and Canada from Quebec and Maine south to Florida and Texas and west to Nevada and Idaho. It prefers neutral to slightly acidic soil, although it will tolerate a pH up to 8.0. Its moisture requirements are high, and it is primarily found in moist habitats such as wet meadows, floodplains, riverbanks, pond shores, stream banks, wet woods, swamps, and marshes, although it will also grow in drier areas such as prairies, fields, and roadsides. (USDA)


Asclepias incarnata is a native, perennial, wildflower growing three to six feet tall. It gets its common name -milkweed- from its white sap, although it has less sap than many of its relatives. The genus was named in honor of Aesculapius, Greek god of medicine, undoubtedly because some species have long been used to treat a variety of ailments. The Latin species name means flesh-colored.

It has long, narrow, lance-shaped leaves that progress in pairs up the stem. Bright pink, white and purple clusters of flowers appear in summer at the tops of the stems. In the fall, blooms give way to distinctive tear-shaped five-inch seed pods that are green when unripe, but harden to brown. The individual seeds are attached to fluffy hairs that allow the seeds to drift on the wind. Swamp milkweed also spreads through rhizomes -roots that grow horizontally from the original plant.(USDA)

Portion of the Plant Used

Roots, fluffy seed hairs.

Traditional Uses

The Chippewa and Iroquois have used an infusion of the roots externally to strengthen the body and heal babies’ navels. The Iroquois and Meskwaki have also used a decoction of the roots and/or aerial portions of the plant as an emetic, diuretic, and de-worming agent. The common name, Pleurisy Root, comes from its once common use to treat lung problems. Swamp milkweed is toxic when taken in large doses. (USDA)

The tough stringy stem fibers have been used to make twine, rope and rough textiles. The downy parachutes (comas) that are attached to each seed are six times more buoyant that cork and five times warmer than wool. Large quantities of milkweed were grown for use as stuffing in pillows and lifejackets during World War II. (Knudsen, H.D. and R.D. Zeller. 1993)

Side Effects, Interactions, and Contraindications

Warning: Swamp milkweed may be toxic when taken internally without sufficient preparation.