Polygonum polystachyum

Wall. ex Meissn.

Himalayan knotweed

PolygonaceaeLeavesSeeds/NutsFlowersPotential hazards — see below

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What to Eat

Edible parts: Seeds, Flowers, Leaves

Leaves can be cooked for use as a vegetable. The seed can be eaten raw or cooked, though it is quite small and fiddly to work with.

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.

Where to Find It

In the Himalayas it grows between 2,000-4,000 m altitude. In Sichuan and Yunnan.

Afghanistan, Asia, Bhutan, China, Himalayas, India, Myanmar, Nepal, Northeastern India, Pakistan, SE Asia, Sikkim, Tibet,

Countries: United Arab Emirates, Afghanistan, Armenia, Azerbaijan, Bangladesh, Bahrain, Brunei, Bhutan, China, Georgia, Indonesia, Israel, India, Iraq, Iran, Jordan, Japan, Kyrgyzstan, Cambodia, North Korea, South Korea, Kuwait, Kazakhstan, Laos, Lebanon, Sri Lanka, Myanmar, Mongolia, Maldives, Malaysia, Nepal, Oman, Philippines, Pakistan, Qatar, Saudi Arabia, Singapore, Syria, Thailand, Tajikistan, Timor-Leste, Turkmenistan, Turkey, Taiwan, Uzbekistan, Vietnam, Yemen

How to Identify

An erect shrubby plant. It grows 2 m tall. It keeps growing from year to year. The leaves are oblong or sword shaped and have a long point. They are 10-25 cm long. They usually have some soft hairs underneath. The flowers are white or pale pink. They have a scent. They are in clusters 15-45 cm long at the ends of branches. The flowers are 6 mm across. Probably now Koenigia polystachya (Meis.) Schuster & Reveal

How to Grow

Succeeds in an ordinary garden soil but prefers a moisture retentive not too fertile soil in sun or part shade. Repays generous treatment. A vigorously spreading plant, it is only really suitable for large areas of ground. Plants are easily mistaken for P. campanulatum. Plants seem to be immune to the predations of rabbits.

Propagation: Sow seed in spring in a cold frame. Germination is usually straightforward. Once seedlings are large enough to handle, prick them out into individual pots and plant out during summer if they have grown sufficiently. If not, keep them in a cold frame over winter and plant out the following spring after the last expected frosts. Division can be done in spring or autumn. Larger divisions can go directly into their permanent positions. Smaller divisions are better potted up and grown on in light shade in a cold frame until well established, then planted out in late spring or early summer.

Medicinal Uses

None known

Other Uses

Plants are very vigorous and can be grown as ground cover, performing well even on stream verges. Space plants approximately 1.2 metres apart in each direction.

Wikipedia

A vigorous perennial reaching 1.8 m (6ft) tall by 1.5 m (5ft) wide at a fast growth rate. Hardy to UK zone 6. Hermaphrodite flowers bloom July to September with seeds ripening September to October. Adapts to light sandy, medium loamy, and heavy clay soils across mildly acidic to basic pH ranges. Grows in semi-shade or full sun, preferring moist soil.

Notes

There are about 50 Polygonum species.

Names & Synonyms

Amldandi, Chuchi, Nia lu, Pang xia mei duo, Sarai, Snya lo, Tror

Possibly now Persicaria polystachyum (Wallich ex Meissner) Gross

References (10)

Ambasta, S.P. (Ed.), 2000, The Useful Plants of India. CSIR India. p 481
Boesi, A., 2014, Traditional knowledge of wild food plants in a few Tibetan communities. Journal of Ethnobiology and Ethnomedicine 10:75
Dobriyal, M. J. R. & Dobriyal, R., 2014, Non Wood Forest Produce an Option for Ethnic Food and Nutritional Security in India. Int. J. of Usuf. Mngt. 15(1):17-37
Flora of China @ efloras.org Volume 5
Guo, C., et al, 2022, An Ethnobotany Survey of Wild Plants Used by the Tibetan People of the Yadong River Valley, Tibet, China. Journal of Ethnobiology and Ethnomedicine p 27
Plants for a Future, The Field, Penpol, Lostwithiel, Cornwall, PL22 0NG, UK. http://www.scs.leeds.ac.uk/pfaf/
Polunin, O., & Stainton, A., 2006, Flowers of the Himalaya, Oxford India Paperbacks. p 346 (As Persicaria polystachyum)
Rawat, G.S., & Pangtey, Y.P.S., 1987, A Contribution to the Ethnobotany of Alpine Regions of Kumaon. J. Econ. Tax. Bot. Vol. 11 No. 1 pp 139-147
Singh, H.B., Arora R.K.,1978, Wild edible Plants of India. Indian Council of Agricultural Research, New Delhi. p 33
N. Wallich, Pl. asiat. rar. 3:61. 1832