Hummingbird clearwing (Hemaris thysbe) on Swamp milkweed, Asclepias incarnata

Swamp milkweed

Pictured above: Hummingbird clearwing (Hemaris thysbe) on Swamp milkweed (Asclepias incarnata). Photo by Mary Keim. Click on terms for botanical definitions. View post as a PDF.

Sometimes known as Pink milkweed, Swamp milkweed(Asclepias incarnata) is an erect, herbaceous perennial with striking blooms that makes an excellent addition to a moist, sunny landscape. It is excellent for attracting butterflies and other pollinating insects, and it the larval host monarch, queen and soldier butterfly caterpillars. It occurs naturally in floodplain swamps, hydric hammocks, wet pine flatwoods and marshes, and typically blooms in summer.

Queen butterflies on Aquatic milkweed, Asclepias incarnata
Queen butterflies nectar on Swamp milkweed flowers. Photo by Mary Keim

Swamp milkweed’s showy pink flowers are slightly fragrant. They are born in compact terminal or axillary umbels. Individual flowers have reflexed corollas and an upright corona — a characteristic typical of milkweed flowers. Leaves are long (up to 6 inches), elliptic to lanceolate, and glabrous. They are oppositely arranged. Stems are stout, glabrous and multi-branched. Seeds are flat and brown with silky white hairs attached. They are born in follicles that split open when ripe. Seeds are dispersed when their silky hairs catch the wind.

The genus Asclepias is named for Asclepius, the Greek god of healing, because some Asclepias species, such as A. tuberosa, are known to have medicinal properties.

Family: Apocynaceae (Dogbane family)
Native range: Most peninsular counties, Wakulla County
To see where natural populations of swamp milkweed have been vouchered, visit www.florida.plantatlas.usf.edu.
Hardiness: Zones 8A–10B
Soil: Wet to moderately dry soils
Exposure: Full sun to minimal shade
Growth habit: 3–6’+ tall, not as wide
Propagation: Seed
Garden tips: Swamp milkweed is one of our most striking native milkweeds. It does best in mixed butterfly and wildflower gardens planted in moist sunny landscapes, but can tolerate occasional drought once established. The plant does well in a container.

Caution: All milkweeds contain a toxic latex sap that may irritate skin.

Swamp milkweed is available from nurseries specializing in Florida native plants. Visit www.PlantRealFlorida.org to find a grower in your area.

For more information on other Asclepias species, see these resources: