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Swamp Milkweed

Swamp Milkweed
Asclepias incarnata
(Order Gentianales; Family Asclepiadaceae)

Swamp Milkweed in bloom (Jennifer Anderson @ USDA-NRCS PLANTS Database)

Swamp milkweed is a milky-sapped plant that can reach up to 5 feet in height.  It has narrow, opposite, 6 inch long and 1 inch wide leaves that taper to pointed tips.  Its stems are branched above with one or more flower clusters at the tips.  Flower clusters are flattened to shallowly rounded heads of numerous individually stalked reddish-pink flowers that often have white centers.  Flowers have 5 reflexed petals that flank 5 erect hoods and are typically less than ¼ inch wide.  Seed pods are up to 4 inches long, paired, narrow, and gradually tapered at both ends.

Flowering Period: July and August


Habitat:  Swamp milkweed is found in wet prairies, marshes, along streams, ponds, and shores throughout the tallgrass prairies.  Usually only found in saturated soils and prefers neutral to slightly acidic soil.

Conservation Status:  Not threatened

Native Status:  Native to the United States

Distribution in Kansas:  Found throughout Kansas along rivers, streams, ponds, lakes, marshes, and wet prairies except for the southwestern quarter of the state.  Swamp milkweed is most abundant in the eastern tallgrass region of the state.  (Kansas distribution of Swamp Milkweed from Dyck Arboretum of the Plains:

Distribution in the North American: Swamp Milkweed is found across the United States and Canada from Quebec and Maine south to Florida and Texas and west to Nevada and Idaho.  (From USDA PLANTS Database:


Human Uses:  Settlers used Swamp Milkweed seed hairs to stuff insulated items like mattresses and pillows.  They are six times more buoyant than cork and five times warmer than wool.  They were used as stuffing for pillows and life jackets during World War II.  Stem fibers were used by many Native American tribes to make rope and fishing nets.

Etymology:  Swamp milkweed gets its common name from the habitat it prefers and its white sap.  The genus was names for Aesculapius, Greek god of medicine, due to the use of some species to treat ailments.  The Latin species name incarnata means flesh-colored.

YouTube: DSCN0265 Monarchs Mating EXC.AVI:

Dyck Arboretum of the Plains:

Ladd, D., & Oberle, F. (2005). Tallgrass Prairie Wildflowers (2nd Edition ed.). Globe Pequot Press.

Image Credits:
Swamp Milkweed by Jennifer Anderson @ USDA-NRCS PLANTS Database.


Dyck Arboretum of the Plains:

Submitted by: Heather Stewart, July 2011

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