Q: I have a problem with a lovely but horribly invasive vine that grows little potatoes on its stem. It sprouts and spreads like a demon – nearly taking over a 3 acre lot! What is it and what can I do about it?
A: Most folks afflicted with this pest call it “Tater Vine” or “Air Potato”. It is actually a variety of yam, scientifically identified as Dioscorea bulbifera. The glossy green leaves are certainly ornamental but the vine’s intrusive nature has placed it very near the top of Florida’s Invasive Plant list. I don’t know why it is not a worse pest here but we can all be thankful for small favors.
Like kudzu, air potato has a large starchy root. The root stores plenty of energy for re-sprouting if the leaves are cut off. A systemic weed killer like glyphosate (Roundup) or triclopyr (Brush Killer, Brush-B-Gon) would give you fair results immediately but you’ll need to re-apply the herbicide every time the leaves reappear. This will be quite a chore on a three acre landscape. You will have to protect other plants from the chemical spray but I think this is the best choice you have.
Air potato (Dioscorea bulbifera) is another non-native, invasive vine in Florida. Covered with large handsome leaves, it can quickly grow 60-70 feet in length, which is long enough to overtop (and shade-out) tall trees. A member of the yam family (Dioscoreaceae), air potato produces large numbers of aerial tubers, potato-like growths attached to the stems. These grow into new plants.
Dioscorea species are cultivated for their edible underground 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. Air potato is believed to have been introduced into Florida as an ornamental and a food plant in about 1905. By the early 1970s it was already recognized as a pest plant throughout the state.
Q: Can air potato ‘taters be eaten?
A: A search of the Internet revealed that they are eaten, steamed or boiled, in Hawaii and Panama but no notes on preparation were found. A few weeks ago, a reader sent in his recipe for cooking the ‘taters with rice, which seems safe enough in small quantities. Eat them if you must….. and while you enjoy them, remember that kudzu can be a dining delight as well.
Q: I have been growing for several years the “air potato” plant you wrote about recently. I grow mine on a fence so the bulblets don’t spread throughout the neighborhood. The tiny “potatoes” are edible and quite good if put into rice near the end of the cooking process (about five minutes seems fine). It is important to harvest as many of the bulblets as possible to reduce the number of additional plants next year.
A: Bon Appetit!
How To Identify Air Potato
Air potato has a winter dormant period when the stems die back to the ground. After dormancy, the underground tubers give rise to stems which quickly grow, often reaching up to 70 feet long by the end of the growing season. The vine’s stem is herbaceous (not woody). The stem is round, not winged, as in D. alata. The large leaves are up to 8 inches long and are heart-shaped (cordate). The leaf blade’s basal lobes are rounded. Leaf veins radiate from a single point. The leaves have long stems (petioles), and are alternate on the stem. Air potato flowers are small, greenish and fragrant, hanging in relatively long clusters (panicles and spikes) up to 4 inches long. The fruit is a capsule of seeds. Air potato plants produce “aerial tubers” that are attached closely to the stems where leaves attach to the stem (axil). These air potatoes are greyish and somewhat irregular. Tubers also grow underground where they may be larger.
Dioscorea bulbifera, R. Br.; L.; Russ. ex Wall. India (Kumaon region, Western Himalayas): axillary tubers cut into pieces, steeped in water, and boiled prior to eating. Hawaii: aerial bulbs eaten. Handy states these are poisonous but is not familiar with detoxification or preparation techniques. Sturtevant records its use elsewhere, but does not refer to its toxicity. Vernacular names – Hawaiian: Ho. English: Air Potato. (India) Kumaon region, Western Himalayas: Genthi. Ref. BHARGAVA, HANDY, NEAL, STURTEVANT.
DIOSCOREA BULBIFERA L. Air potato (E); Name (S). Cultivated in Panama, this is one of the easier species to recognize because of its aerial bulbs. These, and the underground tubers, are usually poisonous raw, but may be peeled, sun dried, and then cooked (!). Underground tubers are best dug when the plant is dying back for the dry season. Some species of Dioscorea have a juice that induces itching (!).
True yams (Dioscorea spp.) were important root vegetables, although one of them, Dioscorea bulbifera, is called the ‘cheeky yam’, because it will make you sick unless it is grated up and thoroughly washed in water before it is used.