Oca is native to the central Andes region of South America where it is an important root crop second only to potatoes. Also popular in New Zealand where it is simply called yam. An herbaceous perennial plant it produces clusters of light red, delicious and nutritious edible tubers that store well and can be eaten raw, roasted and in soups and stir-fries. Succulent clover-like foliage is also edible and good as a green vegetable. Grow like a potato and store the tubers in a cool place for the winter.