Oca

Oxalis tuberosa

Physical Characteristics

Oxalis tuberosa is a PERENNIAL growing to 0.5 m (1ft 8in) by 0.3 m (1ft). See above for USDA hardiness. It is hardy to UK zone 7 and is not frost tender. It is in flower from July to August. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers moist soil.

Distribution

S. America - Colombia, Peru.

Habitats

Cultivated Beds;

Edible Uses

Edible Parts: Flowers Leaves Root Edible Uses: Tubers - raw or cooked[2, 103, 183]. An acid lemon flavour when first harvested, if left out in the sun the tubers turn sweet[183], so sweet in some varieties that they are said to resemble dried figs and are sold as fruits in local markets in S. America[34, 37, 97, 196]. The cooked root is delicious whether in its sweet or acid state, it can be boiled, baked etc in similar ways to potatoes[K]. The tubers tend to be rather smaller than potatoes, with good sized specimens reaching 8cm or more in length. The slightly waxy skin makes cleaning them very easy[K]. They contain about 70 - 80% moisture, 11 - 22% carbohydrate, 1% fat, 1% fibre and 1% ash[196]. The carbohydrate is rich in sugar and easy to digest[196]. Acid types are rich in oxalic acid (up to 500ppm) but sweet forms have much less oxalic acid than is found in potatoes[196]. Edible young leaves and flowers - raw or cooked[34, 37, 103]. Poor quality[33]. Use in moderation, see notes at top of sheet,

Medicinal Uses

None known

Known Hazards

The leaves contain oxalic acid, which gives them their sharp flavour. Perfectly all right in small quantities, the leaves should not be eaten in large amounts since oxalic acid can bind up the body's supply of calcium leading to nutritional deficiency. The quantity of oxalic acid will be reduced if the leaves are cooked. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition[238].