Winged yam
Native to: Southeast Asia
Winged yam was introduced to the Americas by Portuguese and Spanish traders in the 1500s. It is a close relative to air potato (Dioscorea bulbifera). Covered with large leaves, it can quickly grow into the tops of tall trees. Winged yam has disprupted plant communities in natural areas, particularly coastal hammocks in south Florida. Winged yam has widespread populations throoughout Florida.
This member of the yam family (Dioscoreaceae) produces edible underground tubers. (Though most yams contain an acrid component, cooking makes them edible.) The large underground tubers of winged yam can weigh up to 100 pounds. Like air potato, winged yam also produces large numbers of aerial tubers, which are potato-like growths attached to the stems. These grow into new plants. Dioscorea species are cultivated for their edible tubers in West Africa where they are important commodities. Uncultivated forms (as in Florida) however are reported to be bitter and even poisonous. Dioscorea varieties, containing the steroid diosgenin, are a principal material used in the manufacture of birth-control pills. Research has shown that winged yam has antifungal properties.
Winged yam is named after its “winged stem” (wide ridges along the squarish stem). (D. bulbifera has a round stem.) Winged yam has a winter dormant period when the stems die back to the ground. After dormancy, the underground tubers give rise to stems which can quickly grow to 30 feet long. Winged yam plants produce aerial tubers that are attached closely to the stems where leaves attach to the stem (axil). These aerial tubers are greyish-brown and somewhat irregular with a rough, bumpy surface.
Winged yam can form blankets of leaves over native vegetation and can cover mature trees.
Winged yam is not recommended by UF/IFAS. It is a prohibited plant according to the FDACS Florida Noxious Weed Index. The UF/IFAS Assessment lists as prohibited, with high invasion risk. It is listed by FLEPPC as a Category l invasive species due to its ability to invade and displace native plant communities.
Regular monitoring and removal of plants can prevent the spread and establishment of winged yam. Programs to educate homeowners on proper plant identification will also reduce the spread of this species. Native alternatives to winged yam for use in home landscaping or natural areas include moonflower (Ipomoea alba), purple passionflower (Passiflora incarnata), yellow passionflower (Passiflora lutea) and corkystem passionflower (Passiflora suberosa).
Cut back during winter dormant period. New growth will use the dead aerial stems from last year to quickly climb into the tree canopy. Cut vines that are high in trees. Cut bulbils and remove from site and dig up underground tubers if possible.
Dig up underground tubers and dispose.
There are no known biological control agents for winged yam. The biological control, Lilioceris cheni, has been effective on air potato (Dioscorea bulbifera) only.
