Swamp Milkweed

Swamp milkweed is an upright, clump-forming perennial native to wet meadows and stream banks of North America. From mid to late summer it produces showy, domed clusters of small, fragrant pink to rose flowers that draw butterflies, bees, and other pollinators in droves.

As a true milkweed (Asclepias), it is an essential host plant for monarch butterflies, whose caterpillars feed exclusively on milkweed foliage. Despite its swampy native habitat, it adapts well to ordinary garden soil and is far better behaved than the spreading common milkweed, making it a favorite for pollinator and rain gardens.

• Flowers: Small, intricate, pink to rose-purple, in rounded clusters (umbels) at the stem tips; lightly fragrant.
• Leaves: Narrow, lance-shaped, opposite, exuding milky sap when broken.
• Seed pods: Slender, upright follicles that split to release silky-tufted seeds.
• Height: Typically 0.9-1.5 m.
• Habit: Upright, clumping perennial; less aggressive than common milkweed.

Light: Full sun for the best flowering.

Water: Loves consistently moist to wet soil; tolerates ordinary garden moisture but never thrives bone-dry.

Soil: Rich, moisture-retentive soils; great for rain gardens and pond edges.

Temperature: Hardy across a wide temperate range.

Feeding: Minimal; thrives without much fertilizing.

Propagation: Sow seed (cold stratify) or divide carefully. It emerges late in spring, so don't give up on it too soon.

Native to much of North America, swamp milkweed grows in wet meadows, marshes, swamps, ditches, and along the banks of streams and ponds. It is adapted to saturated soils but tolerates drier garden conditions.

It is widely planted in pollinator gardens, rain gardens, and naturalized wetland plantings, and is a frequent component of monarch-conservation seed mixes.