Yacon: An exciting South American tuber to grow this spring

South America is just on the other side of the Pacific Ocean – which is why, climatically, we have a lot in common with many of the countries there. And while our winters may not be as extreme as many parts of South America, nor our summers quite as hot, we can still grow some of the same garden vegetables, especially the continent’s tubers.

What’s more, as changes to our weather patterns mean that New Zealand summers are tending to arrive later than usual, these tubers (which require shorter daylight hours to mature) are exactly what the home gardener is looking for. Yacon is relatively recent tuber to arrive in the country from South America, and if you haven’t tried growing it already, this spring is the perfect time to experiment with this exciting plant.

Yacon

A weighty root vegetable (sometimes spelt with a ‘k’ as in yakon) yacon is a relative of the sunflower, and has some distinguishing characteristics that will surprise you. Although the tuber (which has the texture of a nashi pear) is bland when first harvested, it quickly sweetens up when left to cure on a sunny window ledge. In fact, yacon are so sweet they are regarded as a fruit rather than a vegetable, and are peeled and eaten as apples, or grated into breakfast cereals. For those who live in possum-prone areas where growing fruit can be a challenge, yacon are the perfect alternative as they grow underground, out of reach of unwanted pests. While the plant’s Jerusalem artichoke cousin grows from an edible tuber, yacon grow from rhizomes at the base of their stem. The edible tubers (the part of the plant which is harvested) grow beneath the rhizomes. Yacon are relatively disease resistant apart from a tendency to develop fungal problems if grown too closely together.

The yacon is a long season grower and rhizomes should be planted as soon as possible after the last frost. They enjoy a bed enriched with plenty of humus, so call on all the compost you have at your disposal. Add some well-rotted animal manure into the mix if the compost does not already contain it, and if you have some rotted seaweed, dig that in, too. Plant the rhizomes (which usually come with a piece of stem attached) just under the surface of the ground, allowing about 1 square metre of space for each plant. As the yacon grows, it will require staking. Yacon do not like wet feet but nor do they appreciate it if the soil dries out so keep a water watch over the driest months.

Toward mid-autumn, the yacon displays a small, yellow bloom, rather like a miniature sunflower. If you live in a frosty part of the country, cover the base of your yacon with a pine needle or straw mulch so that when the first frost arrives, it does not damage the plant’s rhizomes which may be protruding above ground level. Once the frost has cut back the foliage, it is time to dig your tubers. If you live in a part of the country that does not receive frosts, the time to harvest is at the end of autumn, at which stage you can cut back the foliage with secateurs before digging.

Take care when harvesting yacon, that you don’t damage the crisp tubers. If necessary, twist them gently from the rhizomes to make a clean break. Without washing, brush off excess soil, and leave the tubers to dry for a few days in a cool, airy place. Once dry, wrap them in newspaper and store in a carton away from the light. Bring a few tubers at a time into a warm place such as a sunny window ledge to sweeten up before washing, peeling and using. Check stores tubers frequently for signs of rot.

Rhizomes should be potted up and stored undercover out of reach of frosts, ready for replanting the following spring. If you live in a frost-free region, you may like to replant your rhizomes immediately following harvest.