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Polygonum hydropiper - L.

Common Name Smartweed, Marshpepper knotweed
Family Polygonaceae
USDA hardiness Coming soon
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].
Habitats Shallow water in ponds, ditches etc and in wet places on land[9, 17].
Range Europe, including Britain, from Norway south and east to N. Africa and temperate Asia.
Edibility Rating    (2 of 5)
Other Uses    (0 of 5)
Weed Potential No
Medicinal Rating    (2 of 5)
Care
Wet Soil Water Plants Full sun
Polygonum hydropiper Smartweed, Marshpepper knotweed


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Polygonum hydropiper Smartweed, Marshpepper knotweed
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Summary


Physical Characteristics

 icon of manicon of flower
Polygonum hydropiper is a ANNUAL growing to 0.8 m (2ft 7in). It is in flower from July to September. The species is hermaphrodite (has both male and female organs). The plant is self-fertile.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It prefers wet soil and can grow in water.

UK Hardiness Map US Hardiness Map

Synonyms

P. fastigiatoramosum. Makino. P. maximowiczii. Regel. Persicaria fastigiatoramosa. (Makino.)Nakai. P

Habitats

 Pond; Bog Garden;

Edible Uses

Edible Parts: Leaves  Seed
Edible Uses: Condiment  Rutin

Leaves and stems - raw or cooked. They can also be made into an acid peppery condiment[183]. They are very hot[116]. The leaves contain about 7.5% protein, 1.9% fat, 8% carbohydrate, 2% ash[179]. The leaves are said to contain rutin[218]. Seed - raw or cooked. It is rather small and fiddly to utilize. The seed is used as a condiment - a pepper substitute[100]. The sprouted seeds or young seedlings can be used as a garnish or added to salads, they are commonly sold in Japanese markets[183]. They are very hot[116, 179].

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.
Antiinflammatory  Astringent  Carminative  Contraceptive  Diaphoretic  Diuretic  Emmenagogue  Homeopathy  
Stimulant  Stomachic  Styptic

Smartweed has a long history of herbal use, both in Eastern and Western herbalism. It is not used very often, and is seen more as a domestic remedy being valued especially for its astringent properties which makes it useful in treating bleeding, skin problems, diarrhoea etc. The leaves are anti-inflammatory, astringent, carminative, diaphoretic, diuretic, emmenagogue, stimulant, stomachic, styptic[4, 9, 21, 147, 152]. They contain rutin, which helps strengthen fragile capillaries and thus helps prevent bleeding[222]. Use with caution[21]. The seed is carminative, diuretic and stimulant[218]. The whole plant, either on its own or mixed with other herbs, is decocted and used in the treatment of a wide range of ailments including diarrhoea, dyspepsia, itching skin, excessive menstrual bleeding and haemorrhoids[218, 254]. A poultice of the plant is used in treating swollen and inflamed areas[257]. In Chinese tests, the plant was ranked 20th in a survey of 250 potential antifertility drugs[218]. A homeopathic remedy is made from the leaves[9]. It is used in the treatment of piles, menstrual pains and other menstrual complaints[9].

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Other Uses

Dye

A yellow-gold dye is obtained from the stalks[106].

Special Uses

Cultivation details

A water plant, growing in shallow water or wet soils. Succeeds in most soils if they are wet and dislikes shade. Smartweed is cultivated for its edible leaves in Japan[116], the variety 'Fastigiatum' (syn P. maximowiczii) is the form normally used[58, 116]. Plants seem to be immune to the predations of rabbits[233].

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Propagation

Seed - sow spring in a pot standing in water or in situ. 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.

Other Names

If available other names are mentioned here

Found In

Countries where the plant has been found are listed here if the information is available

Weed Potential

Right plant wrong place. We are currently updating this section. Please note that a plant may be invasive in one area but may not in your area so it’s worth checking.

Conservation Status

IUCN Red List of Threatened Plants Status :

Related Plants
Latin NameCommon NameHabitHeightHardinessGrowthSoilShadeMoistureEdibleMedicinalOther
Polygonum alaskanumAlaska Wild RhubarbPerennial1.8 -  LMHSNM21 
Polygonum alpinumAlpine Knotweed, Alaska wild rhubarbPerennial1.0 4-8  LMHSNM21 
Polygonum amphibiumWillow Grass, Water knotweed, Longroot smartweed, Water smartweedPerennial0.3 4-8  LMHSNWeWa120
Polygonum arenastrumSmall-Leaved Knotweed, Oval-leaf knotweedAnnual0.3 4-8  LMHSNM230
Polygonum aviculareKnotweed, Prostrate knotweedAnnual0.3 4-8  LMHSNM230
Polygonum barbatumJoint WeedPerennial0.8 -  LMHSNM11 
Polygonum bistortaBistort, Meadow bistort, SnakeweedPerennial0.5 4-7 FLMHSNMWe332
Polygonum bistortoidesAmerican BistortPerennial0.5 4-8  LMHSNM31 
Polygonum bungeanumBunge's smartweedAnnual0.8 0-0  LMHSNM10 
Polygonum coccineumWater SmartweedPerennial0.5 4-8  LMHSNWeWa10 
Polygonum conspicuum Perennial0.6 -  LMHSNM10 
Polygonum convolvulusBlack BindweedAnnual1.2 0-0  LMHSNM100
Polygonum divaricatum Perennial1.0 -  LMHSNDM10 
Polygonum douglasiiKnotweed, Douglas' knotweed, Austin knotweed, Engelmann's knotweed, Johnston's knotweed, Large knoAnnual0.3 0-0  LMHSNDM20 
Polygonum dumetorumClimbing false buckwheatAnnual1.8 0-0  LMHSNM11 
Polygonum equisetiforme Perennial1.0 7-10  LMHNDM10 
Polygonum fugax Perennial0.0 -  LMHSNM30 
Polygonum japonicumJapanese Knotweed, Mexican Bamboo, Japanese KnotweedPerennial3.0 4-10 FLMHSNM330
Polygonum lapathifoliumCurlytop KnotweedAnnual0.8 4-8  LMHSNMWe110
Polygonum limosum Perennial1.8 -  LMHSNM10 
Polygonum longisetumOriental lady's thumbAnnual0.5 0-0  LMHSNMWe10 
Polygonum maackianum Annual0.8 -  LMHSNMWe10 
Polygonum manshurienseAsian BistortPerennial0.8 -  LMHSNMwe01 
Polygonum microcephalum Perennial0.5 -  LMHSNM10 
Polygonum minusPygmy smartweedAnnual0.3 0-0  LMHSNMWe10 
Polygonum molle Perennial2.5 6-9 FLMHSNM21 
Polygonum multiflorumHe Shou Wu, Tuber fleeceflowerPerennial Climber4.5 6-9  LMHSNM23 
Polygonum nepalenseNepalese smartweedAnnual0.3 0-0  LMHSNMWe11 
Polygonum orientalePrince's Feather, Kiss me over the garden gateAnnual1.5 0-0  LMHSNM220
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Botanical References

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Readers comment

These webpages cover a whole range of spices and their known chemical makeup. A very informative source on teh properties of many edible plants.   Jun 4 2011 12:00AM

The tastes relates to chemicals called alkamides, these are typically found in planst such as the Szechuan pepper (Zanthoxylum simulans), Sansho Pepper(Zanthoxylum piperatum), Paracress (Acmella oleracea syn. Spilanthes oleracea).
Gernot Katzer's Spice Pages

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Subject : Polygonum hydropiper  
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