Asclepias sullivanti – Prairie Milkweed

COMMON NAME: Prairie milkweed, Smooth milkweed, Sullivant’s milkweed
SCIENTIFIC NAME: Asclepias sullivanti – named for a Greek god of healing and for
William Starling Sullivant (1803-1873), a botanist who published a book in 1843
listing the plants of Ohio. He also traveled widely studying mosses and became a
leading bryologist.
FLOWER: Pink on stalks about one inch long in a single umbel at the end of the stem
BLOOMING PERIOD: June to July
SIZE: 2 to 3 feet tall
BEHAVIOR: This milkweed develops a deep taproot that makes it difficult to
transplant, but it grows easily from seed. The large leaves have a significant upward
sweep. During drought lower leaves turn yellow and fall off. This also happens
when the seedpods develop.
SITE REQUIREMENTS: It needs full sun in moist to wet soil.
NATURAL RANGE: Central U.S., Michigan to North Dakota, south to Ohio and
westward to Oklahoma. In Wisconsin it is mostly in the southeast, but can be grown
in the Dane County area. It is listed as a Wisconsin Threatened Species.
SPECIAL FEATURES: The leaves are smooth and thick, attaining a size of up to 6 by
3 ½ inches. The central vein is pink or reddish. The leaves are host to the larval
stage of the monarch butterfly. Many insects as well as the ruby-throated
hummingbird are attracted to the nectar and long-tongued bees are efficient in
removing the pollen sac and carrying it to another flower. The foliage contains a
white latex that is bitter and toxic.
SUGGESTED CARE: Be sure it is planted where it gets adequate water.
COMPANION PLANTS: Alumroot, New England aster, smooth aster, bergamot,
boneset, cardinal flower, yellow coneflower, Culver’s root, cup plant, marsh
blazingstar, mountain mint, Turk’s cap lily, turtlehead, Bebb’s sedge, and great blue
lobelia