Have you ever noticed dense thickets around Pinellas County where the trees and bushes are shrouded in tangles of vines that snuff the life out of the plants they engulf?
The likely culprit is the air potato, one of the worst exotic-invasive plant species plaguing Florida. Because of its tendency both to displace native species and disrupt natural processes like water flow and fire, the air potato is considered one of the most invasive species in the state.
A native of Asia, the air potato was first introduced into Florida in 1905. It is believed to have been brought to the Americas on slave ships from western Africa centuries ago. Characterized by broad, heart-shaped leaves, the vine can grow to over 70 feet in length and as much as eight inches a day. Because it cannot support its own weight, it climbs by twining up other plants to capture sunlight.
To my horror, I have found this vine sprouting in my own yard and have found it difficult to completely eradicate. That’s because air potato vines spread easily and are very hard to destroy. The vine reproduces through aerial tubers that form at the base of the leaves. These tubers eventually fall off the vine and sprout new vines in the spring.
Herbicide application is currently the most effective way to control the spread of the air potato, although studies are underway on the use of a beetle as a biological control. The University of Florida IFAS Extension recommends using herbicides containing the active ingredient glyphosate (such as Roundup) or triclopyr (Garlon).
The best time to apply an herbicide is in the spring and summer when air potato is actively growing. Try to pull the vines off desirable plants, pile the vines on the ground and spray them. This will allow the most herbicide to be absorbed into the underground tuber, killing the vine.
When applying herbicide to this plant, try to spray the leaves as much as possible but be careful to avoid over-spraying, which could splatter the chemical onto and kill other plants. For this reason, it’s best to apply herbicides when there is no wind, such as early in the morning. Also keep in mind that you will likely need to apply herbicide to this plant in successive years to fully eradicate it from your yard.
While the vines can be pulled up from the roots, even tiny tubers can shake loose and sprout new vines. Mowing and disturbing air potato vines can contribute to their spread by distributing the tubers over a wider area, so try to avoid doing so if at all possible.
Speaking of the tubers, they can most easily be removed and destroyed during the winter months when the vine is dormant and the tubers are easier to spot. It’s important to dispose of them properly so they don’t spread, such as by taking them to a landfill that will incinerate them. As they do not tolerate freezing temperatures, you can stick them in the freezer overnight for good measure. Just make sure no one in your household tries to boil air potato tubers for dinner; a related, similar-looking plant is highly toxic.
You can learn more about the air potato and methods to control it at http://plants.ifas.ufl.edu/node/133 and http://www.fleppc.org/Manage_Plans/AirpotatoManagementPlan_Final.pdf