Oriental lady's thumb

Polygonum longisetum

Physical Characteristics

Polygonum longisetum is a ANNUAL growing to 0.5 m (1ft 8in). It is in flower from May to June, and the seeds ripen from June to August. The species is hermaphrodite (has both male and female organs). Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist or wet soil.

Distribution

E. Asia - China, Japan, Korea.

Habitats

Bog Garden;

Edible Uses

Edible Parts: Leaves Seed Edible Uses: Young leaves - raw or cooked[105, 177]. A famine food, used when all else fails[177]. Seed - raw or cooked. It is rather small and fiddly to utilize.

Medicinal Uses

None known

Known Hazards

Although no specific mention has been made for this species, there have been reports that some members of this genus can cause photosensitivity in susceptible people. Many species also contain oxalic acid (the distinctive lemony flavour of sorrel) - whilst not toxic this substance can bind up other minerals making them unavailable to the body and leading to mineral deficiency. Having said that, a number of common foods such as sorrel and rhubarb contain oxalic acid and the leaves of most members of this genus are nutritious and beneficial to eat in moderate quantities. Cooking the leaves will reduce their content of oxalic acid. 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].