From the Moche to my garden - the yacon

A yacon plant harvested

on 23 April 2011, 

and cut to show

the white flesh of the

young tuber.

 Yacon harvested on

 19 May 2011.

Last winter I was given some unprepossessing-looking brown tubers to grow. I left them lying around for a couple of months, which meant they were a bit shrunken and wrinkly when I finally placed them in the ground in spring. I put them in a sunny but rather stony spot, waited for a month or so before some leaves started to show, then watered them when I watered the peas on one side and the potatoes on the other. They grew fine heads of large and furry light green leaves. By April I began to wonder if they had grown any extra tubers as well.

I pulled one up and found that they were indeed producing tubers, and I took the photo of one cut in half above. Yesterday I harvested the rest of the crop, and took a peeled and sliced tuber to choir practice to share with my fellow singers, for their amusement. They then asked lots of questions about what they were eating, and I have had to do a bit of research to find out all about the yacon.

Briefly, it is a vegetable from South America, where it is known to have been consumed a thousand years ago. (Yacon are depicted in the marvellous ceramics of the Moche people, who lived in northern Peru from around 100-700 C.E.) It is a crunchy, juicy and slightly sweet vegetable. The taste has been likened to a water chestnut, a melon, and a pear (with a hint of celery). An English name for it is 'Peruvian ground apple', and yacon is supposed to mean 'water root' in the Inca language. Its scientific binomial is Smallanthus sonchifolius, and it is part of the great big daisy (Compositae) family of plants.

It is believed to have fabulous therapeutic qualities, especially for diabetics, as both the roots (the juice from which can be made into syrup) and the leaves (which are made into tea) have a special form of sugar which is not digested. They also have prebiotic properties i.e. they support a friendly gut flora. The yacon was traditionally used therapeutically to help control blood sugar and improve digestion, and more recent scientific studies suggest that there is potential for developing this use.

So far, so amazing – but are they good to eat, and how does one prepare them? They are good in just about any kind of salad, peeled and then sliced, chopped or grated – but add them at the last minute and/or dress them with lemon juice as the white flesh goes brown if left exposed to air. They can be added to stir-fries, curries and other mixed dishes. Since they are a bit bland, they make a good foil to stronger flavours, as in the recipes suggested by Mark Diacono.

Like potatoes (and dahlias and Jerusalem artichokes) yacon tubers can last a long time above ground, and can reproduce from only part of the tuber. They seem to be able to grow well just about anywhere (even 'In the toad's garden' in Denmark) so if you want to grow something a bit different, but not tricky, may I recommend the yacon.

I made yacon tea by steeping three large fresh leaves in a small pot of water for ten minutes. It looked beautiful in a margarita glass - and tasted like old grass clippings. I tried to make yacon syrup by boiling 150g of sliced yacon in 300 ml of water until the liquid was reduced to 100ml, but it was hardly sweet at all. A bit more research suggests that the juice needs to be pressed from the roots, and then then boiled. I doubt that it is worth the bother to do it at home.