Redring milkweed is in the Asclepiadaceae (milkweed) family. It is one of about 115 species that occur in the Americas. Most species are tropical or arid land species. The genus name, Asclepias, commemorates Asklepios, the Greek god of medicine. Some of the milkweed species have a history of medicinal use including common milkweed, A. syriaca (wart removal and lung diseases), and butterfly weed, A. tuberosa (also known as “pleurisy root”, for pleurisy and other lung disease). The specific epithet, variegata, means ‘variegated’ in reference to the two colors on the flowers.
This species like most milkweeds has a deep root stock that helps the plant survive fire and drought. The plant grows to about 1 meter (3 feet) tall, sometimes taller, with 4-6 pairs of opposite leaves. Leaves are more or less elliptical and 8-12 centimeters (3-5 inches) long by 2.5-7.5 centimeters (1-3 inches) wide. The underside is lighter in color than the upper side and may have hairs on it. Flowers are waxy and white, frequently with reddish, pinkish, to purplish rings around the middle, hence the common name. Flowers are 7-9 millimeters (0.25-0.35 inches) long, and are borne in loose to dense hemispherical clusters at the top of the plant. Inflated, but narrow, upright seed pods (follicles) are usually borne in pairs. The fruits of this plant resemble those of purple milkweed (A. purpurascens) and poke milkweed (A. exaltata). Broken leaves and stems produce milky latex.
This milkweed like most milkweeds produces copious amounts of nectar and is an important pollinator plant. The flowers have a sweet odor. Bees, wasps, butterflies, flies, and ants can be seen on its flowers. Redring milk is not an important food plant for monarch butterfly caterpillars, although they can be occasionally found on the plants. The plant tends to be in low densities and in some shade and this may make it harder for monarchs to find it.
Redring milkweed is a species of moist to dry shaded roadsides, woodland, savanna and open forest. It tends to grow in light to moderate shade, but tolerates full sun. It is known from Texas north through Oklahoma and Missouri to Illinois and east to the Atlantic from Connecticut to Florida. It is also known from Ontario.