PlantFiles: Oca
Oxalis tuberosa

Fairly productive tuber-forming food crop (typically c. 1 kg per plant if well grown). Day-length sensitive, so unproductive in areas with early frost in Autumn. Several varieties available. Very attractive foliage, suitable as ground cover. Attractive waxy tubers harvested after the plant has been killed by frost. May be grown like potatoes (earthed up) or alternatively its habit suits bi-cropping with any tall crop such as tomatoes or corn. Some sources are beginning to report mild allelopathic effect on following crops. Delicious roasted! Detailed results of garden-scale trials (in UK conditions) here:
http://oca-testbed.blogspot.com/

I was first made aware of this plant on a trip to Bolivia. The roots there are a fairly common vegetable, especially with the indigenous Aymara and Quechua people. The roots are look like short, rounded, yellow carrots, and are cooked by boiling. The taste is similar to sweet potato, but the texture is firmer, more like a carrot. A very tasty tuber worth growing and eating, and a nice looking foliage plant to boot.

A tuberous crop similar to the potato and having a slightly nutty new potato taste. May also be used in place of wheat as a flour.

Typical trifoliate leaves with silvery soft hairs and bright yellow oxalis flowers. Produces numerous, buff, pink, red or brown tubers, much smaller than a potato and yields about 8lbs of tubers per plant on moderate soil.

This plant is by no means frost hardy, tubers can be lifted and replanted the following year or as I do, left in a large container under glass over the winter and repotted the following year. They do have pests, cheifly in the form of the Oca Weevil, or in my case pet ducks who love the foliage.