Practical
Plants

Polygonum lapathifolium

Curlytop Knotweed

an annual member of the Polygonum genus in the family Polygonaceae.

No photo available

Taxonomy and growth

Life cycle
annual
Height
0.75 m
Fertility
Insects
Flower type
hermaphrodite
Pollinators
Insects

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[8].

Edible uses

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

Young leaves - raw or cooked[2][4]. Seed - raw or cooked. It is rather small and fiddly to utilize.

Plant part
Leaves
Plant part
Seed

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 whole plant is antiseptic and astringent[5]. An infusion has been used in the treatment of stomach complaints and fevers[9]. The plant produces a soft white mass, a froth like that of soap. It is applied externally to burns[10].

Product or use
Antiseptic
Product or use
Astringent
Product or use
Febrifuge
Product or use
Stomachic

Material uses

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

The plant produces a soft white mass, a froth like that of soap. It is used for bathing and washing clothes[10].

Product or use
Soap

Environment

Range
Temperate regions of the northern hemisphere, including Britain. S. Africa.
Habitat
Swampy thickets, shores, damp clearings and cultivated fields in N. America[11].
Light
full sun
Shade tolerance
light shade
Water
high
Hardiness
Zone 5+
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.

Cultivation

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

Succeeds in an ordinary garden soil[1] but prefers a moisture retentive not too fertile soil in sun or part shade[6]. Repays generous treatment[1]. Plants seem to be immune to the predations of rabbits[7].

References

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

    ↩1↩2

  2. Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976-00-00

    ↩

  3. Clapham, Tootin and Warburg. Flora of the British Isles. Cambridge University Press 1962-00-00

  4. Kunkel. G. Plants for Human Consumption. Koeltz Scientific Books 1984-00-00 ISBN 3874292169

    ↩

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

    ↩

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

    ↩

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

    ↩

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

    ↩

  9. Moerman. D. Native American Ethnobotany Timber Press. Oregon. 1998-00-00 ISBN 0-88192-453-9

    ↩

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

    ↩1↩2

  11. Fernald. M. L. Gray's Manual of Botany. American Book Co. 1950-00-00

    ↩

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