Asclepias perennis

Common Names

Aquatic Milkweed, White Swamp Milkweed, Swamp Milkweed

Summary

Asclepias perennis, commonly called Aquatic Milkweed, is an herbaceous perennial native to U.S. wetlands, including floodplains, marshes, swamps, and other constantly wet sites. Typically upright, it forms clumps about 1 to 2 feet tall and 12 to 18 inches wide, with long, narrow green leaves and flat umbels of white to pinkish white flowers that bloom in spring through summer. It produces pendulous seed pods with buoyant seeds capable of floating for months, enabling water dispersal, and contains milky latex. For cultivation, it prefers full sun to partial shade and moist to wet soils, with standing water tolerated temporarily. It is deer- and rabbit-resistant, provides nectar for pollinators, and serves as a monarch butterfly host plant, making it suitable for wildlife-friendly, butterfly, and pollinator gardens. It is commonly used in rain gardens, bog gardens, and margins along ponds or streams, and propagation is via seed.

Lifecycle

Perennial

Height

1-3 feet

Spread

12-24 inches

Hardiness Zones

Zones 6-10

Sunlight Requirements

Ideally Full Sun to Partial Shade.

Soil Type

Moist to wet soils, including clay, loam, and sand, wetland or swampy, water-saturated conditions

Soil Drainage

Moist to wet, poorly drained soils

Soil pH

Tolerates all pH levels

Bloom Color

White

Bloom Time

Spring through Fall

Foliage Color

Green

Leaf Lifecycle

Deciduous

Growth Rate

1-3 feet tall

Seasons of Interest

Spring and Summer

Propagation Methods

Seeds

Attracts Wildlife

Attracts bees, butterflies, and other pollinators