Asclepias subverticillata (Horsetail Milkweed)
Family: Asclepiadaceae (Milkweed)
Asclepias subverticillata is a small-flowered milkweed. Leaves are narrow, often in 3-leaved whorls. Flowers are white to cream-colored. Plant height is mostly 12 to 24 inches, though plants can be taller.  Horsetail Milkweed primarily occurs south of Interstate 70, but is has been found further north, as well. Plants grow on dry, gravelly sites or along ditches and streams.

Compare to Asclepias pumila (Plains Milkweed), which has tightly spaced, alternate leaves. Plains Milkweed is usually less than 12 inches tall.

Vegetation zone:  Plains, Foothills  (3400 - 8600 ft.)
Time of bloom:  June - August
Origin:  Native
Eastern Colorado Wildflowers