Ullucus tuberosus aka Ulluco

Ullucus tuberosus is a small perennial crop in the Basellaceae family. Common names include ulluco, olluco, and papa lisa. Kew lists its native range from Peru to Jujuy, Argentina. Growers have long raised it for food in the high Andes. It grows there at 6,560–13,120 feet [2,000–4,000 metres]. It also grows at lower sites in temperate regions.

The plant has a compact, upright form and makes underground tubers. Sources give heights of about 0.7–1.6 feet [0.2–0.5 metres]. Both PFAF and Useful Tropical Plants also list 1 foot [0.3 metres]. The tubers come in several colours. They can reach about 0.26 feet [0.08 metres] long. Its flowers have both male and female organs. Gardeners can grow it in beds for its food crop.

Ulluco needs sun and prefers moist soil. It grows best in rich, light soil with added leaf mould. Sandy soil and loam both suit it. It can still yield a crop in poor soil. Established plants can withstand some drought. Its preferred soil pH is 5.5–6.5. It also tolerates neutral and mildly alkaline soil. Useful Tropical Plants gives a preferred mean yearly temperature of 12–20°C.

Cold and the length of autumn can limit the harvest. PFAF lists USDA zones 8–10 but calls the plant frost tender. Its growing notes say leaves withstand light frost. Tubers tolerate more cold than the leaves. Reports of strong frost resistance conflict with PFAF's own experience. Tubers form late, so good yields need a mild autumn. British trials as a potato replacement did not succeed. Growers can harvest after autumn frost kills the top growth. Tubers need cool, frost-free storage through winter. Summer stem cuttings root from a single leaf node.

People cook the tubers and use them much like potatoes. Their flesh is starchy and has a mucilaginous texture. Boiling and frying give a taste close to potato. Andean cooks also freeze and dry them to make chuño. The tubers supply carbohydrate and vitamin C, with little fat. In cool storage, they may keep for twelve months. People also eat the leaves raw or cooked. PFAF and Useful Tropical Plants report no known hazards. PFAF lists no medicinal or other non-food uses.