Miller, James H.; Manning, Steven T.; Enloe, Stephen F. 2010. A management guide for invasive plants in southern forests. Gen. Tech. Rep. SRS–131. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 120 p.
Air yam (Dioscorea bulbifera L.), Chinese yam or cinnamon vine (D. oppositifolia L., formerly D. batatas Decne.), and water yam (D. alata L.) are herbaceous, high climbing vines to 65 feet (20 m) that cover shrubs and trees in infestations. They have twining and sprawling stems with long-petioled smooth heart-shaped leaves and dangling potato-like tubers (bulbils) that appear at leaf axils and drop to form new plants. Aerial tubers spread downslope and by water and sprout to form new plants. All species also have large tubers underground that make control difficult, but rarely if ever produce seed. Except for south Florida, all vines die back during winter but can cover small trees in a year, with old vines providing trellises for regrowth.
Management strategies
- Do not plant. Remove prior plantings, and control sprouts and seedlings.
- Bag and dispose of all aerial yams (bulbils) in a dumpster or burn.
- Treat when new plants are young to prevent seed formation.
- Pull, cut, and treat when fruit are not present.
- Burning and cutting treatments have minimal control due to large underground tubers.
Recommended control procedures
- Thoroughly wet all leaves with one of the following herbicides in water with a surfactant before aerial bulbils form: Garlon 3A or Garlon 4 as a 2-percent solution (8 ounces per 3-gallon mix). Chinese yam bulbils will take up the herbicide; the other species must be collected and destroyed (not composted).
- For safety to surrounding plants, cut climbing plants just above the soil surface and immediately treat the freshly cut stem with Garlon 3A in a 50-percent solution (6 quarts in a 3-gallon mix).
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