Wild yam is native to woods and thickets in eastern North America. The perennial vine climbs on trees and can grow to 10 feet. It thrives in partial to filtered sun and does best in rich soil. Unlike sweet potato yams, the wild yam is not eaten due to the bitter taste of the root. Wild yam is cultivated as a natural medicine.
Wild yam (Dioscorea villosa) is also known as colic root. There are two species, one a native plant to North America. The other species of wild yam is native to China. A perennial vine, wild yam blooms with clusters of white or yellow flowers, tinged with green. Long, broad heart-shaped leaves with downy undersides grow along its reddish thin stems. The stems can reach a length of 30 feet, often growing up into the trees. The knotty, woody rootstock of the wild yam is cylindrical, narrow and crooked. The pale brown horizontal root has long creeping runners.
Introduce wild yam into the garden by planting the eyes of the rootstock in the fall. Another option is to start the vines in flats or cold frames and introduce them into the garden in the spring.
Break the root into pieces, each with one eye and plant them about 2 to 3 inches deep. You also can break the eyes off the rootstock and plant them individually. Plant them in well-drained, rich soil, and keep the plant well watered until the vine is about a foot high. A nearby tree, trellis or bush will give the vine and opportunity to climb. The whole root can be planted if establishment of a vine for a striking focal point in a garden is desired.
The roots of the wild yam are harvested and dried when the plant is 3 years old. The mature roots are seldom thicker that 1/2 inch. Leave some of the rootstock with eyes for continued growth.
Early American Indians used wild yam root to ease labor pain and to treat intestinal problems and asthma. Wild yam root is also used in Chinese medicine for indigestion, dysentery, asthma and rheumatoid arthritis. Abdominal cramps, infertility, impotence and hysteria alll have been treated with wild yam root in Ayurvedic medicine, an early medicine practiced in India.
The pharmaceutical industry used wild yam, along with other species of Diasorea in preparations of steroids. Wild yam root contains diosgenin, a compound that can mimic the effects of progesterone and estrogen in animals. Diosgenin was used in the manufacture of early contraceptives.
Because wild yam root contains diosgenin, there is a possibility, although not proven, that it can produce an estrogen-like effect. People with a family history of hormone-related cancers should consult a medical professional before taking wild yam root. Nursing mothers and pregnant women should avoid wild yam. Herbs can interact with medications or supplements, or cause allergic reactions, and their use should be discussed with a medical professional.