mashua, yacon, oca: growing edible andean tubers, with help from peace seedlings

OCAHER PLANT-BREEDER FATHER, Dr. Alan Kapuler, has been turning me and other gardeners on to unexpected edibles for decades, but today it’s Dylana Kapuler who’s coaching me patiently, this time about Andean tubers with names like yacon, mashua and oca (above) that are making their way around the world and into gardens. They’re nutritious, prolific and just plain fascinating—and now you can try them.

The pre-Columbian Indians of the Andes domesticated more starchy root crops than any other culture, but only the potato caught on as a staple worldwide.

“The others have seldom been tried outside South America, yet they are still found in the Andes and represent some of the most interesting of all root crops.…” said a 1989 report called “Lost Crops of the Incas: Little-Known Plants of the Andes with Promise for Worldwide Cultivation” from the National Research Council.

“They come in myriad colors, shapes, and sizes,” the report added. “They belong to botanical families as different as those of mustard, legumes, and sunflower. They tend to be richer in vitamins and proteins than today’s conventional roots. And collectively, they show enormous adaptability to difficult conditions.”

All of that is what attracted Dr. Alan Kapuler to them, and gradually the longtime family farm and seed company in Corvallis, Oregon, now called Peace Seedlings and run by Dylana Kapuler and Mario DiBenedetto, has built up stock.

Full instructions come with each shipment of starts, but here are some basics:

YACON tubersyacon (Smallanthus sonchifolius)

A relative of dahlias and Jerusalem artichokes, yacon forms large, edible tubers, above, with russet skins and a unique characteristic—or should I say lack of a characteristic: They have no eyes (the growth points we are familiar with on potatoes, or sweet potatoes, for instance).

That means propagation must be by division of the plant’s central crown, or by cuttings (or from micropropagation in tissue culture, if you happen to run a laboratory!). Crowns are overwintered indoors like other tender bulbs, and split in the spring before planting back outdoors.

YACON to plantLike a tender bulb you wish to give a headstart, pot up the small starts, above (on which you will see eyes) as soon as they arrive, and transplant outdoors 1 to 3 feet apart after frost.

Yacon, to 5 feet or taller, has big, fuzzy leaves and an enthusiastic downward energy that will tap down even into clayey soils. It loves water, especially late in the season when tubers are bulking up. Harvest after light frost, but protect from freezes.

Eating yacon tubers is said to improve digestive health, “and by promoting the growth of probiotic bacteria may be supplying us with B vitamins as well,” says Alan Kapuler.

Yacon can be eaten raw, or cooked, but will be tastier after they cure; at first they are bland like a water chestnut, says Dylana. A sign they’re cured, a couple of weeks out of the ground, is that their skin darkens to a maroon color.

Last year the Peace Seedlings team made yacon syrup for sale at the farmers’ market (photo at the bottom of the page)—a concoction that has even made its way to the Dr. Oz show.

OCA tubers on plateoca (Oxalis tuberosa)

Oca is a Peruvian and Bolivian food staple, and rivals beets as the most colorful vegetable you’ll ever grow. The small, odd-shaped tubers, look as if a tightly closed pine cone had crossed with a squid–and then gone psychedelic. (If you can visualize that description, which probably reveals something about my mental status, please don’t tell the guys with the straitjackets.)

The plants look like other Oxalis, with shamrock-shaped foliage. Get them into the ground after the last killing frost, says Dylana, planting them as you would a potato, spacing about 6 inches between tubers.

Dylana and Mario “earth up” the tubers (again, like potatoes) as they grow.

Because they are daylength-sensitive, oca plants won’t start tuberizing underground until after the equinox (September 22 in 2014). Be sure to keep them well-watered during that last part of the season in particular for maximum yield. Some years the tubers overwinter in Corvallis, Oregon, where Peace Seedlings’ farm is.

Oca tubers vary in color, and also in flavor (from tangy to sweet), and will sweeten after curing. They can be used raw in salad, or cooked in any way you might a potato (mashed, roasted with other root vegetables).

mashua tubers eace seedlingsmashua (Tropaeolum tuberosum)

This nasturtium cousin (those are its tubers, above) has a vining habit–whether sprawling or up and over something–and hot-colored flowers full of nectar that hummingbirds love. The foliage is beautiful, and nasturtium-like (below, a plant in Peace Seedlings’ field).

mashua growingAgain, the tubers (which to me have that pine cone-squid combo look, too–sorry!) are planted like potatoes, 1-2 feet apart, and benefit from being hilled up at they grow—and also from having some support.

Mashua is daylength sensitive, but seems to tuberize a bit earlier than oca, says Dylana. Tubers are crunchy and peppery when raw, she says (like the more familiar garden nasturtiums) but have a hint of anise when cooked till soft. (Cooking takes the spiciness away.)

And here’s something I really love to hear: Mice and voles won’t eat mashua, and in fact will tunnel around them, it seems. Maybe I should put some in every bed here that the little devils seem to haunt.

YACON syrup from Peace Seedlingsmore from peace seedlings

  1. Bill W. says:

    Great article! Perhaps 2014 will the the year that Andean tubers really catch on in North America. I can attest that Peace Seedlings grow some really nice oca.

    1. margaret says:

      Hi, Bill. And they are tasty! I can’t wait to get my start of mashua and see that great looking vine going mad here…the others are potted up!

  2. Mark says:

    Sweet! They have a mixed selection of the Oca. I don’t think I have enough room for the others but love the flowers on that Mashua.

  3. I am blown away by those tubers! What an education–thank you. Also, I loved seeing the European Wild Ginger in your photograph with your clippers on top. That is one of my favorite ground covers and many don’t know about it. It’s a winner year round.

  4. Mary Cafarelli says:

    Clicked link for 10 tips to get started in the garden – got tuber info instead????????????????????????????????

  5. Beth says:

    I grew up in Bolivia and we ate oca all the time. Bolivians have a habit of putting the oca on a pan out in the sunshine for a day or two before roasting- as I recall it makes them sweeter. And they are soooo yummy! Thanks for sharing. I wonder if I would have any luck with them in zone 5.

    1. Joan Gross says:

      I spent much of the last 2 years in Ecuador and they also leave oca in the sun to gather sweetness. Then you can boil it with cinnamon and make a nice thick drink.

    1. margaret says:

      Hi, Dave. Fascinating, aren’t they? I feel like trying some oddballs this year, making a little room for a few experiments!

  6. Elle says:

    The book, Seeds of Change by Ken Ausubel, about the start up of the seed company, is a great read and the contributions of Alan Kupular are detailed throughout. I read it years ago but it stuck with me because it’s a great gardening story!

    Love yacon raw in salads, is a two year crop, yes? But have never heard of the other two and look forward to trying them, thank you!

  7. Rebecca says:

    Wow, synchronisity at work? We just received an order of mashua and yacum and I’ve returned to your web site only to find this wonderful article! I’m rather excited about mashua’s flowers.

  8. Heike says:

    Lovely article about these South American tubers! Thanks! I live in New Zealand and grow ocas, mashua and a bit of yacon. I would like to know, can you still eat Mashua, when it is greenish or would that be poisonous as it is in potatoes? Thanks.

  9. Peggy says:

    I am interested in trying these but my question is: how do you peel such small tubers? Or do you? I have tried to peel kohlrabi with a potato peeler and could not because it is so small so that is why I hesitate to grow such small things. But maybe you are supposed to just cut it and eat it like it is?

    1. margaret says:

      Hi, John. You will have to correspond with Peace Seeds directly to see if they can help. Follow the link in the story to their website.

  10. Julie Martinson says:

    I’ve only grown Tropaeolum tuberosum so far, but the gorgeous
    orange blossoms come in November here in the PNW, so the
    hummers just get a short but enthusiastic feast before frosts.
    Looking forward to trying some of the others for fun & nutrition;
    great article!

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