Polygonum bungeanum

Turcz.

Prickly Smartweed

Polygonaceae Edible: Leaves, Seeds Potential hazards — see below

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Summary

Annual plant reaching 0.8 m in height. Hermaphrodite flowers bloom July to August with seeds ripening August to September, pollinated by insects. Grows in light sandy, medium loamy, or heavy clay soils with mildly acid to basic pH. Tolerates semi-shade or full sun and prefers moist soil.

Description

A herb. It grows each year from seed. The stems are erect and 30-80 cm tall. The leaves are 4-13 cm long by 1-3 cm wide.

This description is brief — help expand it

Edible Uses

Leaves can be eaten raw or cooked. Seeds are also edible raw or cooked, though they are rather small and fiddly to use.

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.

Distribution

It is a temperate plant. In northern China it grows from sea level to 1,700 m above sea level.

Where It Grows

Asia, China, Japan, Korea, Russia,

Cultivation

We have very little information on this species and do not know if it is hardy in Britain, though judging by its native range it should succeed outdoors in most parts of the country. The following notes are based on the general needs of the genus. Succeeds in an ordinary garden soil but prefers a moisture retentive not too fertile soil in sun or part shade. Repays generous treatment. Plants seem to be immune to the predations of rabbits.

Propagation

Sow seed in spring in a cold frame; germination is generally free and easy. Once seedlings are large enough to handle, prick them out into individual pots and plant out during summer if they have reached sufficient size, or overwinter in a cold frame and plant out the following spring after the last expected frosts.

Other Uses

None known Special Uses

Notes

There are about 50 Polygonum species.

Synonyms

Persicaria bungeana. (Turcz.)Nakai.

References (4)

Bull. Soc. Imp. Naturalistes Moscou 13(1):77. 1840
Duke, J.A., 1992, Handbook of Edible Weeds. CRC Press. p 154
Flora of China @ efloras.org Volume 5
Plants for a Future database, The Field, Penpol, Lostwithiel, Cornwall, PL22 0NG, UK. http://www.scs.leeds.ac.uk/pfaf/