Asclepias incarnata

Common Names

Swamp Milkweed, Rose Milkweed, White Indian Hemp, Swamp Silkweed, Pleurisy Root, Marsh Milkweed, Pink Milkweed, Rose Milkflower

Summary

Asclepias incarnata, swamp milkweed, is a native North American herbaceous perennial that forms upright clumps about 3–5 feet tall, with long opposite lance-shaped leaves and dense pink to mauve flower clusters in summer. It contains a milky sap with toxins, and after flowering produces seed pods with silky-haired seeds dispersed by wind; the plant attracts butterflies and other pollinators and serves as a vital larval host for monarch butterflies. It thrives in full sun to partial shade and moist to wet soils, tolerating clay, and requires consistent moisture rather than prolonged drought. Propagation can be by seed (often with cold stratification) or by division, and it self-seeds prolifically via buoyant seed pods. It is deer-resistant and generally pest- and disease-free, though oleander aphids and milkweed stem weevils can occur. In landscapes it suits butterfly gardens, rain gardens, borders, and wetlands restoration, and it is suitable for cut flowers; deep taproots make transplanting challenging, so a permanent site is recommended.

Lifecycle

Perennial

Height

3-5 feet

Spread

24-36 inches

Hardiness Zones

Zones 3-9

Sunlight Requirements

Ideally Full Sun, tolerates Partial Shade.

Soil Type

Moist to wet, loamy soil

Soil Drainage

Moist to wet soils

Soil pH

Neutral to slightly acidic soil

Bloom Color

Pink

Bloom Time

Summer to Fall

Foliage Color

Green (dark green; may turn purple in fall)

Fall Foliage Color

Purple to Purplish

Leaf Lifecycle

Deciduous

Growth Rate

Slow-growing, takes 2–5 years to reach about 1–1.5 metres.

Seasons of Interest

Spring, Summer, and Fall

Propagation Methods

Seeds, Cuttings, Division

Attracts Wildlife

Bees, butterflies, and other pollinators; hummingbirds and birds are not consistently documented