Air Potato

What is air potato?

Air potato identification is simple once the bulbils show up: brown, potato-like lumps that form where the large, heart-shaped leaves join the twining stem. Native to Africa and Asia, this member of the yam family was brought to Florida in the early 1900s as an ornamental and food plant. It is now one of the most aggressive vines in the Southeast, and USDA PLANTS lists it under the name air yam.

It can grow about 8 inches in a day and cover a small tree within a year. Its big leaves cast such dense shade that the plants and trees beneath it struggle, and old dead vines act as a trellis for the next year's growth. Every bulbil can become a new plant, and underground tubers keep resprouting, so an infestation can take over an area quickly if no one manages it. Burning or cutting alone does little, because the tubers stay alive underground.

Air Potato identification: what to look for

Look for bulbils first, then check the leaves and stems. The vine dies back in winter, but bulbils on the ground and old dead vines in the trees often remain, which helps you find it in the off-season.

• Leaves: Alternate, heart-shaped at the base with a long, pointed tip, 2 to 10 inches long, on long stalks. Edges are smooth. The main veins curve out from the base and come together again at the tip, giving the leaf a quilted, puckered look. The base of the leaf stalk wraps the stem.
• Stems: Smooth, hairless, round green stems that twine around supports and climb high into trees. They are not angled or winged.
• Bulbils: Aerial tubers that form in the leaf axils, from pea size to about 5 inches across. Some are light tan and smooth, others dark brown and rough; they are often dimpled and look like small potatoes. Even small ones can sprout.
• Tubers: Round underground tubers sit in the top few inches of soil and feed the vine's regrowth each spring.
• Flowers: Rarely seen. Tiny greenish-white flowers hang in spikes from the leaf axils. Florida populations are almost all female, so seed is rarely produced.
• Seasonal habit: Vines die back in winter, and new shoots come up from tubers and bulbils in spring.

Where it grows in the United States

Air potato is established in Florida, Georgia, Alabama, Mississippi, Louisiana and Texas, as well as Hawaii and Puerto Rico. It is most abundant in central and south Florida, where winters are mild, and a USDA Forest Service field guide describes it spreading from Florida into neighboring Gulf Coast states. It has even been found in the mountains of North Carolina, where it is on the state invasive plant council's watch list.

It prefers moist soil rich in organic matter and grows in a wide range of places: pond and marsh edges, drainage canals, disturbed woods and thickets, forests and floodplains, waste areas and urban yards. It can also move into undisturbed natural areas, though it is less common in pine woods and right along the coast. Bulbils that fall into water can be carried to new sites, so creeks and ditches help it spread.

Air Potato look-alikes

A few plants get mixed up with it:

• Wild yam (Dioscorea villosa): A native yam that never forms aerial bulbils. Its upper leaf surfaces are hairy, and its leaf stalks do not wrap the stem.
• Chinese yam (Dioscorea polystachya): Another invasive yam. Its stems are angled, its leaves can be alternate or opposite, and its bulbils are warty and only about an inch long.
• Water yam (Dioscorea alata): Found mainly in Florida. It has four-angled, winged stems with reddish nodes, leaves that are often opposite, and oblong, rough bulbils.
• Greenbriers (Smilax spp.): Native vines that can be mistaken for air potato, but they often have thorns and green to purple-black berries, and they never form aerial tubers.

How to get rid of air potato

Pulling, digging and mowing: Mechanical removal is the recommended first step. Pull or cut vines before bulbils form, which is usually by late summer, and dig out the underground tubers. Collect bulbils from the ground, ideally in winter after the leaves drop, when they are easier to spot. Bag every vine piece, tuber and bulbil and put it in the trash; do not compost them, and do not move them to a new spot. Expect to repeat the process for four to five years, since tubers and missed bulbils keep producing new vines.

Cultural control matters most, because the right conditions keep it from coming back.

• Make a winter bulbil hunt a yearly habit; collect, bag and trash every one you find.
• Never share, plant or move bulbils or tubers. Planting air potato is illegal in Florida.
• In Florida, leave the air potato leaf beetle alone. This small orange-red beetle, released in 2012, feeds only on air potato and has been reported to cut vine cover by about 90 percent in native plant communities.
• Check treated areas each growing season for at least four to five years and pull new sprouts while they are small.

Herbicides: UF/IFAS lists glyphosate and triclopyr as the active ingredients for air potato. Foliar sprays work best from August through October and should wet all the leaves before bulbils form; triclopyr may perform better early in the season and glyphosate later. Near plants you want to keep, cut the vine and treat the fresh cut stem right away instead of spraying. Herbicide sprayed on the vine will not reliably kill bulbils that have already formed or fallen, so collect and destroy them by hand. Plan on repeat treatments every year for four to five years to use up the tubers and bulbils in the soil. Many infestations are near ponds and canals; at those sites use only a product labeled for aquatic areas. Use only products labeled for your site, follow the label exactly, and remember the label is the law. If you hire someone to spray, make sure they hold your state’s pesticide applicator license; the rules for each state are in our pesticide applicator license guide.

Keeping it from coming back

Air potato spreads almost entirely by bulbils and tubers, so the main prevention steps are to never plant or share it, to dispose of bulbils in the trash, and to keep them out of ditches and ponds where water can carry them. In Florida it is listed as a noxious weed, which makes planting or moving it illegal.

Outside its core range, catch it early. It has been found as far north as the North Carolina mountains, so if you see heart-shaped leaves with potato-like bulbils on a vine, confirm the identification with your county Extension office and remove it before it builds up a supply of tubers.

Questions we get about air potato

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