Swamp Milkweed, Asclepias incarnata

Swamp Milkweed

Asclepias incarnata

Benefits:
Sun Shade:
Bloom Time: Summer
Zones: 3, 4, 5
Soil Conditions: Clay, Loam, Sand
Soil Moisture: Moist, Wet
Color: Pink, Red
Fragrance: Yes
Height: 3 - 5 feet
Spacing: 1 - 2 feet


Description

Swamp Milkweed (Asclepias incarnata) is an erect, clump-forming, native plant which is commonly found in swamps, river bottomlands and wet meadows. It typically grows 3-4 feet tall on branching stems. Small, fragrant, pink to mauve flowers (1/4 inch wide), each with five reflexed petals and an elevated central crown, appear in tight clusters (umbels) at the stem ends in summer. Flowers are uncommonly white. Narrow, lance-shaped, taper-pointed leaves are 3-6 inches long. Stems exude a toxic milky sap when cut. Afterwards, successfully cross-pollinated flowers are replaced by seedpods. The seedpods (follicles) are 3-4" long and narrowly lanceoloid-ellipsoid in shape. Immature seedpods are light green, smooth, and glabrous, turning brown at maturity. Each seedpod splits open along one side to release its seeds. These seeds have large tufts of white hair and they are distributed by the wind during the fall. The root system is rhizomatous, from which clonal colonies of plants occasionally develop.

Habitats include open to partially shaded areas in floodplain forests, swamps, thickets, moist black soil prairies, low areas along rivers and ponds, seeps and fens, marshes, and drainage ditches. Swamp Milkweed can be found in both high quality and degraded habitats.

Flowers are very attractive to butterflies as a nectar source. In addition, swamp milkweed is an important food source for the larval stage of Monarch butterflies.

Easily grown in medium to wet soils in full sun. Surprisingly tolerant of average well-drained soils in cultivation even though the species is native to swamps and wet meadows. Plants have deep taproots and are best left undisturbed once established. Foliage is slow to emerge in spring.

Plant Notes and Herbal Uses
  Berries are toxic
  Have long taproots that resent disturbance
  Has milky white sap that may irritate skin
  Susceptible to mealybugs and aphids
Further Information

Wild Ones of the Fox Valley Area
Prairie Nursery
Wisconsin DNR
Wisconsin Native Plant Nurseries