Description

Chinese yam, or cinnamon vine, is an herbaceous, deciduous, perennial twining vine native to China. It is found throughout the eastern U.S. from Arkansas to Florida and as far north as Vermont with most current occurrences in the central portion of that range. It was introduced for ornamental, food, and medicinal purposes and probably escaped cultivation in the mid-1990s. It can form dense masses of vines that cover and kill native vegetation including trees within a variety of moist disturbed habitats. The leaves are halberd-shaped with a pointed tip, a concavity between leaf base and tip, long parallel veins, a long stalk, are 3-6 in. long by 3-4 in. wide and opposite to alternate (near the tips). The stems are rounded, thin and wiry. It rarely flowers. Reproduction is mainly by aerial potato-like tubers (bulbils) in leaf axils and by underground tubers. Several vines look like Chinese yam including two native species – whorled wild yam (D. quaternata) and common wild yam (D. villosa) which have heart-shaped leaves, small hairs on upper leaf surfaces, lack aerial tubers and twine right to left. Other vines that might be confused with it include native greenbrier (Smilax sp.) which lacks the aerial tubers, typically has thorns and blue to purple berries, non-native field bindweed (Convolvulus arvensis), which has alternate leaves and showy trumpet-like flowers, and morning-glory (Ipomoea sp.) which has heart-shaped, alternate leaves.