Common Name: swamp milkweed
Type: Herbaceous perennial
Native Range: Northeastern and southeastern United States
Zone: 3 to 6
Height: 4.00 to 5.00 feet
Spread: 2.00 to 3.00 feet
Bloom Time: July to August
Bloom Description: White, pink, mauve
Sun: Full sun
Water: Medium to wet
Suggested Use: Naturalize, Rain Garden
Flower: Showy, Fragrant
Tolerate: Deer, Clay Soil, Wet Soil
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.
Swamp milkweed is an erect, clump-forming, Missouri native plant which is commonly found in swamps, river bottomlands and wet meadows throughout the State. It typically grows 3-4' tall (less frequently to 5') on branching stems. Small, fragrant, pink to mauve flowers (1/4" 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" long. Stems exude a toxic milky sap when cut. Flowers are followed by attractive seed pods (to 4" long) which split open when ripe releasing silky-haired seeds easily carried by the wind. Flowers are very attractive to butterflies as a nectar source. In addition, swamp milkweed is an important food source (albeit somewhat less important than upland species of Asclepias) for the larval stage of Monarch butterflies.
No serious insect or disease problems.
Sunny borders, stream/pond banks, butterfly gardens. A good plant for low spots or other moist areas in the landscape.