A grass-like sedge grown for its small, sweet, starchy underground tubers.
Tiger nut (Cyperus esculentus, family Cyperaceae) is a perennial, grass-like sedge with single stems 10 to 90 cm tall, which spreads by underground runners. The tips of the runners swell into small round or oval tubers 10 to 18 mm long, sometimes a metre or more from the parent plant in heavy clay. It is sometimes grown commercially for its edible tubers, and a cultivated variety, var. sativus, has larger tubers.
Its original home is unknown; it is now a widespread weed from the tropics to the temperate zone, as far north as Alaska, and is classed as Least Concern on the IUCN Red List (2013). In the tropics it grows up to 2,000 metres, best at 14 to 26°C with 500 to 1,000 mm of rain a year. It prefers moist sandy loam in sun or light shade but grows in most soils and tolerates occasional flooding; the tubers survive in frozen ground down to about -15°C. In warm climates it is a serious weed of farms, ranked with its relative Cyperus rotundus among the world's worst weeds. Tubers are ready 90 to 120 days after planting, and the crop is propagated by replanting them.
Source: Useful Tropical Plants database (Fern, K.).
Tubers and their extracts are used traditionally as a digestive aid and diuretic.
Tubers are eaten raw or dried, and ground or soaked to make the popular tiger-nut drink.
Grown from tubers in sandy soils, and also spreads readily as a weed in cultivated fields.