Across much of the Deep South, there’s a vigorous and attractive climbing vine called the “air potato.” Its Latin name is Dioscorea bulbifera. This basically pest-free plant has the strange habit of forming dangling bulbils (aerial roots) along its vines. When fall comes and the day lengths shorten, the vines dry up… and the bulbils, which look sort of like little potatoes, fall to the ground for the winter. In spring, each one grows into a new plant. By this manner, air potato plants spread happily over acres of woods… and have become the bane of native plant enthusiasts, forestry departments and homeowners. You see, the air potato isn’t originally from the US – it’s from Africa and Asia. And though some forms are edible… and are a great staple… other forms are inedible since they contain a toxic steroid that can mess with your reproductive system. Though I’ve done hours of research on D. bulbifera, I still haven’t come across a way to know which wild types are edible and which aren’t. This is unfortunate, since it’s very prolific.
To make things more confusing, Dioscorea bulbifera has a cousin, Dioscorea alata, also sometimes called an “air potato,” which is always edible… and that’s the plant we’ll consider today. The reason I started with D. bulbifera is to make sure you don’t randomly start digging roots in the wild and eating them. Unless you like sterility, stay away from air potatoes unless you know for sure they’re an edible type.
Unlike D. bulbifera, D. alata, the “winged yam” (also known as ube, purple yam and roughly one billion other regional names), has dark and misshapen bulbils that look like grotesque charred animal organs. The “air potatoes” on D. bulbifera are pocked, light tan and much rounder, with a look that’s reminiscent of little moons or asteroids.
Like its cousin D. bulbifera, the winged yam is also classified as an invasive species, at least in Florida. Though it’s not nearly as aggressive, someone decided to add it to the list years ago. This makes it hard to find for sale – though wild specimens can be obtained on occasion.
Do you ever feel like there’s a conspiracy against us when it comes to growing staple foods and useful plants? Along with opium poppies (which can be used safely to treat diarrhea, headaches and toothaches), mesquite trees (which have excellent wood, nitrogen-fixing ability and edible pods), hemp (which has amazing medicinal, fiber and biomass uses) and water spinach (which will produce lots of nutritious leaves in a tiny space), you can stick the winged yam on the list of exceptional species which are just not appreciated by The Powers That Be. Look – you almost certainly won’t get in trouble for growing this thing, but you’re not allowed to sell or spread it around. Unlike, say, Cannabis sativa, it’s basically unrecognizable except to plant geeks, and it doesn’t really go as well with cheetos and scratchy old Bob Marley records. Plus, it’s just a somewhat invasive plant, not a drug. Nobody is going to form cartels, write rap songs or become prostitutes over winged yams. Seriously.
Now… look at a pretty picture of one of these things:
The How and Why of Growing Winged Yams
The winged yam is a perennial species of true yam (not to be confused with sweet potatoes) that grows huge, delicious roots with very little care from the gardener. Basically, you plant a bulbil in the fall, winter or spring, then wait. In late spring, when the yam has decided it’s warm enough, a little vine will pop out of the ground and start looking for something to climb. That vine will grow rapidly and reach for the sky, whether in shade or sun. As the year progresses, the plant gathers plenty of energy from sunlight and stores it in a rapidly expanding tuber beneath the earth. As fall arrives, bulbils form at various leaf nodes and dangle in the air as the vine yellows and dies back. At this point, the root can be dug – or it can be left in the ground for another year to continue growing in size.
Why would you want to grow these puppies? How about this: the roots can hit 80lbs or more. Not only that – they’re delicious. I know a lot of people brag about the flavor of various wild stuff they’ve tried, but in the case of this yam, it’s not hyperbole. The tubers taste better than potatoes. (As an aside, some cultivars are purple, though it seems that the white varieties are more common in the States.) Its crops like the winged yam that really help you grow those high calorie foods your family needs.
Beyond the size and flavor, this is a “set and forget” crop. If you plant these in your garden, all you have to do is wait. It will grow in bad soil, beneath trees, in abandoned lots, along fences, without watering, etc. This is probably where some of its “invasive” cred comes in. It lives and it makes plenty of food without any work on your part. It’s also unrecognizable as food to most people. Yet overseas, this plant is literally a lifesaver in some communities. Yes, D. alata can invade native ecosystems; however, what if we simply ate it instead of calling in guys with backpack sprayers full of RoundUp(TM)? I’ve done my fair share in harvesting them from the woods – and if you keep an eye on the plants you grow, you’ll easily be able to keep them from escaping. And even if they do escape – it’s not like the state is ever going to win this fight. D. alata has been kicking around here and there for almost a century. Having edible yams in the woods simply means there will be more wild food available during times of crisis or famine.