SafePlants

Prairie Milkweed (Asclepias sullivantii)

Prairie Milkweed, scientifically known as Asclepias sullivantii, is also commonly called Sullivant's Milkweed and Smooth Milkweed. It was the winner of the 2015 Green Thumb Award for Best New Product.

Taxonomy and Nomenclature

• Scientific Name: Asclepias sullivantii Engelm. ex A. Gray
• Family: Asclepiadaceae (Milkweed Family)
• Named for: William Starling Sullivant, an American botanist.
• Synonyms/Common Names: Prairie Milkweed, Sullivant's Milkweed, Smooth Milkweed.

Distribution and Habitat

• Native to North America, particularly the central United States and the Great Plains, including Illinois.
• Concentrated in the Midwest.
• Typically grows in moist to wet prairies and can also be found in sandy, loamy, or rocky calcareous soils, including roadsides.
• Becoming rarer, especially north of Iowa, throughout most of the Tallgrass Prairie region.

Morphological Characteristics

• Perennial herbaceous plant reaching 2-3 feet tall.
• Erect, unbranched central stem that is relatively stout, terete (round in cross-section), light green, and glabrous (smooth).
• Leaves are described as smooth.
• Features large, domed clusters (umbels) of deep pink to pinkish-white or purple-tinged green flowers, about 1/3 inch long, with 5-parts.

Ecological Role

• Important nectar source for many butterflies, including Monarchs, whose white eggs can be found on the undersides of the leaves.
• Leaves serve as a food source for butterfly larvae.
• Less aggressive than Common Milkweed.

Quirky Facts

• Prairie Milkweed creeps slowly by rhizomes, making it a good candidate for butterfly gardens.
• Sometimes referred to as the "little brother" of common milkweed due to its shorter stature and better behavior in gardens.

Further Resources

• Endangered Resources Program provides identification information, photos, and links.
• Dave's Garden is a community where people share tips and ideas for gardens.