Yam Bean, Jicama, Mexican Yam

Pachyrhizus erosus

Physical Characteristics

Pachyrhizus erosus is a CLIMBER PERENNIAL growing to 6 m (19ft) by 1.5 m (5ft) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 10. It can fix Nitrogen. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: neutral and basic (mildly alkaline) soils and can grow in very alkaline soils. It cannot grow in the shade. It prefers moist soil.

Distribution

Central America - Mexico.

Habitats

Edible Uses

Edible Parts: Root Seedpod Edible Uses: Edible root - raw or cooked[296 ]. Crisp, sweet and juicy, it tastes somewhat like an apple when raw and a water chestnut when cooked[296 , 301 ]. The root stays crisp and does not discolour after being cut[296 ]. It also stays crisp after being cooked, which makes it a popular substitute for water chestnuts in Chinese cooking[301 ]. A starch extracted from the root is used in custards and puddings[301 ]. The root is harvested before it matures and becomes fibrous, when the plant has been growing for about 6 months and the tuber weighs about 2 kilos[200 ]. Mature tubers can reach 2 metres long and weigh up to 20 kilos[200 ]. Young seedpods - cooked and used as a vegetable[46 , 300 , 418 ]. They must be thoroughly cooked in order to destroy the poisonous principle rotenone[200 ].

Medicinal Uses

None known

Known Hazards

Seeds and leaves are poisonous[296 ]. The leaves, mature seedpods and the seeds contain a poisonous glucoside[300 , 418 ]. (Seed is poisonous if ingested Parts of plant are poisonous if ingested )