Dioscorea bulbifera, the infamous Air Potato
The “Cheeky Yam, or Yam on the Lamb
Yam B, Dioscorea bulbifera, is definitely second best to Yam A, Dioscorea alata. Why is Yam B, the D. bulbifera second best? For two reasons. It requires more work to prepare it to eat, and doesn’t grow as big as D. alata. Let me tell you right now I have not yet dug up a Yam B tuber, but not from lack of trying. Despite decades of looking I’ve never found one. My friend, Dick Deuerling, has however, did. He’s the author of “Florida’s Incredible Wild Edibles.” Dick was a stickler for taxonomy so when he says he dug up a D. Bulbifera tuber, not a D. alata tuber, boiled it twice and ate it, I believe him. I’d ask him to do it again but he’s past 90 and doesn’t get around well anymore.
The yam in question, D. bulbifera, ((Dye-os-KOH-ree-uh or in Greek thee-oh-skor-REE-uh)) is the green scourge of Central Florida, ….and South Florida, ….and North Florida…. watch out Georgia here she comes…. It was sent to a researcher in Orlando in 1905 as a possible ornamental and food crop. He reported it would be a dangerous plant to Florida but didn’t kill the plants he experimented with. A little over a century later it now carpets many parts of the state.
That D. bulbifera can be an attractive ornamental is attested by tourists mistakingly taking it home to plant. That it was a potential food crop is debatable. While there may be one species of D. bulbifera there are many varieties. I have noticed, for example, that some have smooth tan round in-the-air bulbils (probably Asian backgound) and others have dark brown bumpy round in-the-air bulbils with tan pimples (probaby African background.) What variety was sent to Orlando was not recorded.
D. bulbifera’s underground root is always referred to as toxic but also eaten in some places. How’s that for ambiguous? And it gets worse, the …. in-the-air bulbils… wrongly called “air potatoes” apparently vary in toxicity, some edible some not. While the bulbils are constantly called toxic by authorities rumor persists they are edible (with special preparation.) In fact I had a visitor from Brazil a couple of years agoy while I had some D. bulbifera bulbils (Asian: Smooth and tan) on my desk. He said his mother cooked them all the time. I asked him to ask her how she does it. (Crushes, dries, bakes, leaches then uses.) On the other hand Dick had two friends boil D. bulbifera in-the-air bulbils and had to go to the hospital (Asian or African not known.) To make matters worse some writers make no linguistic distinction between the above ground in-the-air bulbils and below ground (in the dirt) roots compounding the confusion by calling them both “tubers. ” And technically the underground tubers are not roots but rather “adventurous stem material.”
Yam A, the Alata on let with in-the-air bulbils, on the right is Yam B, with in the air-bulbils. No root is shown.
The D. bulbifera has large round ball to heart-shaped leaves and a round stem. It climbs at eye level from your lower right to upper left (called the S-twist) and has in-the-air bulbils that are round, brown and lumpy (African) or round smooth and tan (Asian) hence the nickname “air potato vine.” And to add to the confusion, Yam A, the Dioscorea alata, (uh-LAT-tuh) has dark brown bulbils as well but they tend to be 1) cylindrical and or 2) very misshapen, neither round or cylindrical, L-shaped, Y-shaped, or a lumpy lump. D. Bulbifera’s in-the-air bulbils are, to my knowledge, always round regardless of color. D. bulbifera can grow a root about the size of a softball (occasionally to a basket ball,) but apparently does not grow a large root too often if rarely in Florida. That would explain why I have never found one. In fact, I became so frustrated with the D. bulbifera, Yam B, I put it on the back burner, the way in the back, for over a decade.
Many years later I became a fan of Ray Mears, a British bush crafter. I ordered some of his DVDs and one of his books about wild edibles in England. Unexpectedly, the Dioscorea bulbifera came up. One of Mear’s episodes was about the Aborigines in Australia. They dig up two kinds of yams, one called “long yam” and one called “cheeky yam.” They steam roast them for a couple of hours then eat the “long yam” immediately but not the cheeky yam.” They grate the cheeky yam then leach it in a flowing stream overnight. Then they eat it. No botanical name was given for either yam. But when I was reading his book Mears happens to mention in passing there is one non-edible yam in England. Then he said it is similar to the one the Aborigines eat in Australia, the D. bulbifera. Well, as one might expect, that caught my attention. I was beginning to think my friend Dick was the only one who ever found a D. bulbifera root to eat but apparently the Aborigines had found them, too. Alas, we don’t know what varieties.
Researching yams again, this time with the internet, I discovered the “long yams” the Aborigines eat are, Dioscorea transversa. The D. transversa (trans-VER-sa) like the D. alata, twists when it grows, lower left to upper right, he Z-twist (as does Yam C, the Dioscorea polystachya mistakenly called D. oppositifolia.) The D. bulbifera, however, twists lower right to upper left, the S-twist. By now I was getting the idea that readily edible yams at eye level climb from your lower left to upper right. Z-twist, then behind. The ones that twist the other way, S-twist, need special preparation or are not edible at all. That may seem like a small observation but it took about a dozen years to sort out.
So I do know two things. Dick has eaten the D. Bulbifera undergound root and I have eaten the D. Alta’s underground root. In Dick’s book he says he boiled the root twice to get rid of the bitterness. Then, after peeling, he used it just like cooked potato. In Australia, to remind you, the Aborigines roast it for a couple of hours, grate it, and then leach it overnight in a flowing stream. I know Dick’s method works for Yam B found here in Florida. I don’t know if the Aborigines’ method would work with Yam B’s here. If I ever find one, I will try both ways and let you know.
And what of the bulbils? The bulbils of some D. bulbifera are reported as edible but they require special preparation as mentioned above. Just boiling will not do it. Often their preparation is peeling, sun drying (read long term chemical decay, not short term in an oven) then boiling. Another report is they are soaked then boiled. As third says they are cooked with lye, a method used with some horse chestnuts. A fourth says none of them are edible anyway.
My suspicion is there are different varieties of D. bulbifera and some may be edible in-the-air bulbils. What we do know is that even where they are eaten they are cut open to see if they turn brown quickly. Those that are are not used. And, in someplaces even after being careful in selecting the Yam B in-the-air bulbils and preparing them the are fed to a dog first to make use.
Green Deane’s “Itemized” Plant Profile
IDENTIFICATION: Dioscorea bulbifera: ”Air potato vine.’ Large heart-shaped leaves, alternating, stem round, climbs from lower right to upper left. Bulbils usually tan, round and smooth, Asian, or round and dark brown with light dimples, African. Underground root roundish, can be lumpy and distorted when grown in hard soil.
TIME OF YEAR: Fall, September to December. For two months the vine dies back making locating difficult.
ENVIRONMENT: Yams do well in sun or partial shade and prosper with ample rainfall. They require good drainage, and therefore, are often planted on mounds or ridges.
METHOD OF PREPARATION: Undergound roots, should you find one: Boil in two changes of water, peel, then slice or mash it, or bake it or chill it and use in a “potato” salad. Make sure it has absolutely no bitterness. I consider the in-the-air bulbils of the D. bulbifera as not edible. If they are it involves considerable process using multiple cooking methods.
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{ 25 comments… read them below or add one }
Does ne one know where I can buy some of the potatoes vine plants??
Buy them? They are a noxious weed in Central Florida. You can’t even give them away. As as it is the lesser of all the yam, why do you want some? They would also become invasive in a similar warm climate.
Yes I have some. They make a beautiful climbing vine. Let me know
if I you are still interested.
http://www.OneGreenWorld.com carries two species of Dioscorea, or ‘Cinnamon Vine’ both sold as producing edible tubers: D. batatas, also called ‘Chinese Yam’ (two varieties/cultivars); and D. nipponica or ‘Japanese Yam’. The D. nipponica is also said to produce edible above ground ‘tubers’.
Both species are listed in their catalog as hardy to USDA zone 4.
http://www.RaintreeNursery.com also lists ‘Cinnamon Vine’ D. batatas in their catalog.
Both companies offer a wide variety of unusual edible plants, ery useful for those wanting a ‘normal’ looking edible landscape in their yard – which can help keep neighbors & officials happy. Edible Landcaping in Va is another source of unusual and interesting edible plants.
Often companies that sell such things have the wrong name which then makes one suspicious of what they say it can be used for.
“Winged Yam (D. alata) vines twine to the right, whereas air potato (D. bulbifera vines twine to the left” Invasive Plants by Sylvan Ramsey Kaufman and Wallace Kaufman
Clockwise and counterclockwise are based upon the position of the viewer. That is why I say “at eye level” either lower left to upper right, or lower right to upper left — at eye level.
Cinnamon Vine or Chinese Yam (Dioscorea oppositifolia) twine counterclockwise from an underground tuber that can be 3 feet long. Kaufman and Kaufman
Clockwise and counterclockwise are based upon the position of the viewer. That is why I say “at eye level” either lower left to upper right, or lower right to upper left — at eye level.
There are varieties of Dioscorea bulbifera that are very edible. In some places they have been cultivated for many years as a food crop. The wild type in FL is not edible. ECHO in Fort Myers grows the edible form and gave me a tuber to grow at one point. I have another friend from Vero beach who is also growing the edible form and she recently gave me a bunch of sprouting bulbils to plant. She has been growing them for years and refers to them as purple yam. The edible form looks different from the wild form, when it first comes up the stems and leaves are a purple color. The wild form looks very different… I have both growing just feet away from each other and as I pull up the toxic ones to remove them it is very easy to distinguish which is which. I have eaten them, many people around the world eat them. They take no extensive preparation, they are a food crop prepared just like any other yam. The inside of the yam underground is a dark purple color and the bulbils are the same on the inside as the underground tubers. The air bulbils are edible, not just the tuber. The cultivated varieties are less invasive due to their edibility. The toxic ones sit there without being eaten and re-sprout, our goats won’t even touch them.
In his book Perennial Vegetables, Eric Toensmeier has several pages about this specific crop with great detail on how to grow and prepare it. He claims that in the future the question will be the ecological damage of NOT growing air potato because of its potential as a no-till perennial staple crop providing starch. ECHO also has info on this crop.
What is the vibe’s shape? Which way does it twist at eye-level (Z or S) and are the leaves singular or in pairs?
The leaves are singular. I don’t know what you mean about the vibe… explain a little better.
The Perennial Vegetables book does classify this as the Bulbifera, I double checked. I highly recommend that book for info on this plant. This is one of the author’s favorite vegetables and writes extensively about this plant.
I recently visited a favorite park in Miami. It is a lovely hammock/hardwood area but lately has become very overgrown with Dioscorea Bulbifera. I fear that if left unchecked, the vine will soon entirely cover and possibly destroy this location. I have even considered donating some of my time and attempting to remove some of the overgrowth. Do you know if this is worth the time in trying to remove the climbing vine or am I blowing against the wind? The small “air potatoes” are seemingly everywhere on the ground and ready to sprout new vines galore.
Great article. My friend has tons of these in her yard, and thanks to you, now knows what these pesky vines are. By the way, according to the “Chinese Materia Medica, third edition” by Bensky, Clavey and Stoger”, Asian D. bulbifera’s underground tubers are used in Chinese medicine for psoriasis, insect bites, and coughs. However, it is also listed as toxic, with different side effects depending on the individual, and the book doesn’t really tell you how the roots are prepared for medicine.
Hey. It turns out my “air potatoes” were actually D. alata.
Regardless, check this article out. I would do anything to get some of these varieties.
http://naldc.nal.usda.gov/download/CAT87208471/PDF
They D. bulbifera, are everywhere here in Florida are famine food at best. There are varieties of that species which are not edible.
UP HERE IN atlanta i have the bulbiferous variety, i believe. They look like miniature replicas oh an idaho potato, round with the little spots on them. I was taught they were edible. While ive never eaten a huge quantity..for days at a time. Ive never felt any ill effects. As for preparation i washed them and sauteed them in butter. Thats it. I DIDNT CONSIDER THEM FAMINE FOOD…THEY ARE JUST LIKE LITTLE POTATOES TO ME. Am i in the wrong? Or do i possibly have a safe variety?
They might be yam C bulbils.
The ones here in Florida…. If I eat them, are they poisonous ? Will I get sick, or what ?
If you boil the root twice, no but they (D. bulbifera) rarely root in Florida. The air potatoes are full of steroids and hormones that will make you sick.
I just moved in to a lovely cottage in an older neighborhood in a south Louisiana city. The whole area is very green with a lot of mature landscapes, both cultivated & wild/opportunistic. The neighboring house is for sale and has an untended garden overgrowing onto my property. I have a young son and wanted to identify the vines, of course, to make sure they pose no threat of any type. I believe one of my encroachers is this “air potato” or “yam b” vines. It is an attractive vine with large heart shaped leaves and does look like a domesticated ornamental & is lovely the way it decorates the lattice on the patio. It is producing round to oval brown potato looking bulbs with light bumps on them. It is starting to yellow in places as if it is dying back though we have had a very temperate fall thus far. If my son does not ingest these pods growing from the vine, I take it that it poses no more of a threat than some other established plants that are poisonous (like the mature azaleas with blooms that are toxic if ingested). Is this correct? I have photos, is there an email address or other way to submit for positive or close to it, identification?
Round and tan bulbils are to be avoided. Round and brown with bumps is in a fuzzy area. I generally say no to those as well.It is mishapen ones we are interested in and the lead topic in the Dec 4th newsletter. In the long run the air bulbils while toxic are not usually fatally so. They are full of steroids and hormones which is what sends you to the hospital should you eat even cooked ones. It is best just to avoid the above ground parts. They do not pose a contact threat like poison ivy would.
So would these plants be toxic to dogs? Our dog recently died due to the ingestion of something, we think in the yard…after many tests we are still in the dark. Just curious- I think we have some of this in our yard.
i have no idea with this plant. my father asked for it from his friends (in Indonesia). they said that it is Japanese Potato and can be eaten. so my father planted it and it grow well to the top of mango tree. the bulbils (I think) are green with some pimples on them and turn brown the next days. they are rather round shaped, like potato.
And this morning, my father picked three brown bulbils, not in the ground, and tried to fry one. We peeled and sliced it like potato. The flesh is quite tricky because of the latex so I soaked it first. I poured a little salt, then fry them. I looked at the light green flesh that hasn’t been fried, and it turned brown. We ate some and it taste quite sweet. But I was anxious about it so I searching on internet to have some information.
There’s no complete information in Indonesia websites so I searched the English. But there are still some ambiguous information. I’m still confused. Is it poisonous? can it be eaten?
Green with pimples? Never heard of them being that color. I have seen them round and tan, or, round and brown with tan freckles. I have not seen them green with pimples. Did you see the articles on Yam A and Yam C? In some countries there are varities of Disocroea bulbifera that are edible. Perhaps you have one, or, you ate a young one. Many “wild” yams are not edible because they have steroids and hormones in them that can upset the body’s function.