Swamp Milkweed (Asclepias incarnata)

Bring on the Monarchs.

Around our area swamp weed appears to be almost as common as Common Milkweed. It can be identified by its significantly finer leaves and smaller flower heads. Like other milkweeds, it has an uncommon ability to support one of our most showy butterflies, the monarch. It’s sap, mildly poisonous to humans and many species of animals and birds, is tolerated by the monarch who absorbs the poison as a caterpillar munching on the plant’s leaves and becomes, itself, poisonous. What a super power!

Here in Cottage Grove, you’ll find swamp milkweed all over in the sun. It grows happily in the GDS school prairie patches, McCarthy Park, in undeveloped lots along the roadside, and in my garden. Like an increasing number of gardeners, I allow it to grow wherever it arrives in the garden to make space for the monarchs. It seems to be less likely than Common Milkweed to appear in unexpected places in the yard, though, and blends in well to flower beds.

Historic Range

Swamp milkweed’s native range covers most of the continental US, with the exception of the Western coastal states, Arizona, and Mississippi.


Per Peterson’s Wildflowers:
“Note the relatively narrow lance-shaped leaves. Smooth. The dull pink flowers are in relatively small umbels. 2-4 ft. Swamps, wet ground. Most of our area. June-Aug.

Wildlife Supported

Monarch caterpillars, milkweed tiger moth caterpillars, and milkweed bugs can all eat the sap of the milkweed without becoming poisoned themselves, but few other insects or animals can.

Bees, other butterflies and flies can all safely use the flower’s nectar.

Culinary Uses

Coming soon.

Medicinal Uses

Coming soon.

Craft Uses

The fluff from milkweed pods can be used as stuffing.
Pods were used as Christmas tree decorations in the past.
Pods can also be used in fairy gardens.
Stems are hollow and make good tubes for solitary bee houses.


No references found yet.

Diseases and Threats

Milkweed’s biggest threat is the lost of wild spaces, like hedgerows and prairies, where they grow and thrive.

Plant Communities

Coming this summer…