The wild yam is native to North America and naturalized throughout the warmer regions of the world. Approximately 800 species make up the genus Dioscorea — a group of tropical and subtropical climbing plants. While some yam species produce tasty, edible tubers, the tubers of D. villosa are bitter and used primarily for medicinal purposes, especially to relieve abdominal cramping.
Common Names: China Root, Colic Root, North American Wild Yam, Rheumatism Root, Wild Yam
Description: Deciduous vine up to 30 feet long; heart-shaped leaves; small, greenish white flowers; creeping woody roots with tuberous rhizomes
Hardiness: To Zone 6
Flowering: June to August
Parts Used: Roots and tuber
Range/Habitat: Native to North America, naturalized throughout the warmer regions of the world; edges of woodland areas
With strong anti-inflammatory properties, wild yam root has a history of medicinal use for cramping or contractions in the pelvic area, including false labor pains, menstrual cramps, uterine spasms, gallbladder pain, and intestinal spasms and cramps. Wild yam contains a steroidlike compound called diosgenin that once was used in contraceptive hormones such as birth control pills. Though wild yam is now widely promoted for menopausal symptoms, studies have found it to be no more effective than a placebo. Many wild yam creams (mostly marketed to ease menopausal symptoms) contain human progesterone created in a laboratory, often synthetically derived from diosgenin.
Caution: As a precaution, pregnant women, nursing mothers, and women with a history of hormone-related cancers should avoid wild yam.
How to grow it
Found in damp woodland areas, wild yam thrives in rich, well-drained soil in sun or partial shade. Plant root divisions in spring or fall, or plant seeds or bulbils in spring. Commercial preparations use the dried root, which is harvested in fall.
The Chief’s Yams
On the island of Pohnpei, in the Federated States of Micronesia, related yam species are a traditional source of food. Yams are also grown on that island for ceremonial presentation to the Chiefs. During the yam feast, tubers of the species Dioscorea alata are dug up, ceremonially presented, and then replanted so that they can continue to grow. I have seen yams of this type that weighed nearly 250 pounds. Local stories tell of the presentation of even larger yams — these yams are said to be the size of small cars and must be carried on poles by 10 or more men!