Swamp Milkweed

Asclepias incarnata Apocynaceae

Growth habit




Native distribution

Native to the Finger Lakes Region, Ne. and SE. U.S.A.


A 2-4' tall moisture-loving plant with mauve flowers.
Light: full sun to part shade.
Moisture and Soil: wet to moist.


Seed Treatment and Storage: Moist cold stratify 30-60 days at 40°F then bring to 70°F in seed starting mix or similar medium.

Biocultural value

A strong tea made with the whole plant was given to stimulate the kidneys. The Chippewa and Haudenosaunee used swamp milkweed stem fibers to make a strong, multipurpose cordage (rope). Medicinally, the plant, especially the root, was used widely as a kidney and urinary aid, cathartic, diuretic, and emetic.

The statements above were sourced from:

Native American Ethnobotany Database: http://naeb.BRIT Native American Ethnobotany Database.org/

Wildlife value

Swamp milkweed and common milkweed (Asclepias syriaca) are the preferred host plants of the monarch butterfly (Danaus plexippus). Swamp milkweed also serves as a larval host plant for the queen butterfly (Danaus gilippus) and late-season nectar source for a variety of butterflies and moths, including great spangled fritillaries (Speyeria cybele), red admirals (Vanessa atalanta), hummingbird clearwing moths (genus Hemeris), and skipper butterflies (family Hesperiidae). Bees and wasps are swamp milkweed's primary pollinators, carrying pollen masses (called pollinia) between flowers. The flowers are also visited by a variety of wasps, ants, flies, beetles, and bugs. Mammalian herbivores avoid the toxic foliage.



Poisonous description

All species of Asclepias are distasteful to livestock and pets. Swamp milkweed can be toxic if ingested and has been reported to cause poisonings in sheep, cattle, and goats. Leaves, stems, and fruit contain the cardiac glycosides desglucosyrioside and syrioside.


Robison Herb Garden, Purvis Road Wetlands Natural Area

Source of plant

North Creek Nurseries, Lazy S's Farm Nursery, Krissy Boys, The Plantsmen, The Flowery Branch


Densley branching, somewhat thick-stemmed perennial reaching 1.75 m in height; leaves 5-15 cm long, linear-elliptic to narrowly ovate, opposite; inflorescences often paired, axillary, held towards ends of stems; corolla lobes white to pink, hood stalked.

USDA Hardiness Zone


Special characteristics

medicinal/pharmaceutical, butterfly plant