Practical
Plants

Polygonum barbatum

Joint Weed

a perennial member of the Polygonum genus in the family Polygonaceae.

No photo available

Taxonomy and growth

Life cycle
perennial
Flower type
hermaphrodite

Uses

Toxicity

Toxicity warning. The historical record reports a hazard for this plant. Do not use it to decide which parts are safe to eat or use medicinally.

This section contains historical Plants For A Future notes marked noncommercial.

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[5].

Edible uses

This section contains historical Plants For A Future notes marked noncommercial.

Tender young leaves and shoots - cooked as a vegetable[8]. They have a somewhat pungent flavour[2].

Plant part
Leaves

Medicinal uses

Historical medicinal uses. These records describe reported uses. They do not establish safety or effectiveness. Ask a qualified health professional before using any plant medicinally.

This section contains historical Plants For A Future notes marked noncommercial.

The seeds are used to relieve the griping pains of colic[6]. The root is astringent and cooling[6]. A paste of the root is used externally in the treatment of scabies[8].

Product or use
Astringent
Product or use
Carminative
Product or use
Parasiticide

Environment

Range
E. Asia - Himalayas to western and southern China
Habitat
Depressions in shaded situations, 1700 - 1900 metres in the western Himalayas. Streamsides, wet areas and the sides of water from sea level to 1300 metres in wesern and southern China[7].
Light
full sun
Shade tolerance
light shade
Water
moderate
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

This section contains historical Plants For A Future notes marked noncommercial.

Seed - sow spring in a cold frame. Germination is usually free and easy. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer if they have reached sufficient size. If not, overwinter them in a cold frame and plant them out the following spring after the last expected frosts. Division in spring or autumn. Very easy, larger divisions can be planted out direct into their permanent positions. We have found that it is better to pot up the smaller divisions and grow them on in light shade in a cold frame until they are well established before planting them out in late spring or early summer.

Cultivation

This section contains historical Plants For A Future notes marked noncommercial.

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 could succeed outdoors at least in the milder parts of the country. The following notes are based on the general needs of the genus. Succeeds in an ordinary garden soil[1] but prefers a moisture retentive not too fertile soil in sun or part shade[3]. Repays generous treatment[1]. Plants seem to be immune to the predations of rabbits[4].

References

  1. F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00

    ↩1↩2

  2. Stuart. Rev. G. A. Chinese Materia Medica. Taipei. Southern Materials Centre

    ↩

  3. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩

  4. Thomas. G. S. Perennial Garden Plants J. M. Dent & Sons, London. 1990-00-00 ISBN 0 460 86048 8

    ↩

  5. Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. 1995-00-00 ISBN 0-7513-020-31

    ↩

  6. Chopra. R. N., Nayar. S. L. and Chopra. I. C. Glossary of Indian Medicinal Plants (Including the Supplement). Council of Scientific and Industrial Research, New Delhi. 1986-00-00

    ↩1↩2

  7. Flora of China 1994-00-00 http://flora.huh.harvard.edu/china/

    ↩

  8. Manandhar. N. P. Plants and People of Nepal Timber Press. Oregon. 2002-00-00 ISBN 0-88192-527-6

    ↩1↩2

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