Japanese knotweed
Japanese knotweed (Fallopia japonica, syn. Polygonum cuspidatum, Reynoutria japonica) is a large, herbaceous perennial plant, native to eastern Asia in Japan, China and Korea.
A member of the family Polygonaceae, Japanese knotweed has hollow stems with distinct raised nodes that give it the appearance of bamboo, though it is not related. While stems may reach a maximum height of 3-4 m each growing season, it is typical to see much smaller plants in places where they sprout through cracks in the pavement or are repeatedly cut down. The leaves are broad oval with a truncated base, 7-14 cm long and 5-12 cm broad, with an entire margin. The flowers are small, creamy white, produced in erect racemes 6-15 cm long in late summer and early autumn.
Closely related species include giant knotweed (Fallopia sachalinensis, syn. Polygonum sachalinense) and Russian vine (Fallopia baldschuanica, syn. Polygonum aubertii, Polygonum baldschuanicum).
Other English names for Japanese knotweed include fleeceflower, Huzhang, Hancock's curse, elephant ears, donkey rhubarb, sally rhubarb, Japanese bamboo, American bamboo, and Mexican bamboo (though it is not actually a bamboo).
In Japanese, the name is "itadori" (usually written in katakana). There are also regional names, and it is sometimes confused with sorrel.
Japanese Knotweed is a primary commercial source of Resveratrol supplements. Huzhang root extract is a traditional Chinese medicinal treatment. It is also known as He Shou Wu, and the prepared herb is used as a blood tonic.
Japanese Knotweed is considered an invasive pest in much of the US, UK, and elsewhere.
Japanese Knotweed
Japanese knotweed vids
Spread of the knotweed
Japanese knotweed was first introduced to Europe and North America in the late 19th century for ornamental use, for planting to prevent soil erosion, and sometimes as a forage crop for grazing animals. It is sometimes considered an invasive species or weed. It is a frequent colonizer of temperate riparian ecosystems, roadsides and waste places. It can be found in 39 of the 50 United States (PUSDA) and in six provinces in Canada. The species is also common in Europe. In the U.K. it was made illegal to spread Japanese knotweed by the Wildlife and Countryside Act 1981, and is listed by the World Conservation Union as one of the world's 100 worst invasive species. Uses
Japanese knotweed flowers are valued by some beekeepers as an important source of nectar for honeybees, at a time of year when little else is flowering. Japanese knotweed yields a nice monofloral honey, usually called "bamboo" honey by northeastern U.S. beekeepers like a mild-flavored version of buckwheat honey (a related plant also in the Polygonaceae).The young stems are edible as a spring vegetable, with a flavor similar to mild rhubarb. In some locations, semi-cultivating Japanese knotweed for food has been used as a means of controlling knotweed populations that invade sensitive wetland areas and drive out the native vegetation.
Both Japanese knotweed and giant knotweed are important concentrated sources of resveratrol, replacing grape byproducts. Many large supplement sources of Resveratrol now use Japanese knotweed and use its scientific name in the supplement labels. Japanese knotweed is harvested because of its year round growth, and robustness in different climates, although it is still considered a troublesome weed.
Japanese knotweed is a concentrated source of emodin, used as a nutritional supplement to regulate bowel motility. "Extract from the roots of Polygonum cuspidatum is used in traditional Chinese and Japanese herbal medicines as a natural laxative. The active principle responsible for the laxative effect is emodin, present in its natural form as a complex of its analogs. It has been reported that emodin has a mild laxative effect in doses of 20 to 50 mg per day."
Japanese knotweed
Japanese knotwed gifts
Japanese Knotweed Growing in Worcestershire, UK Art Photographic Poster Print by Martin Page, 30x40
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The Japanese Knotweed Manual by Lois Elizabeth Child
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Japanese Knotweed, Flowering Photographic Poster Print by Kidd Geoff, 48x64
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Japanese Knotweed, Reynoutria Japonica Photographic Poster Print by Geoff Kidd, 36x48
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Japanese Knotweed Growing in Worcestershire, UK Art Photographic Poster Print by Martin Page, 24x18
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Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens (Hardcover)
Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens
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An informative and engaging account of the ecological interactions between plants and wildlife, this fascinating handbook explains why exotic plants can hinder and confuse native creatures, from birds and bees to larger fauna.
Snippets
As little as 0.7g of rhizome, a piece the size of your little finger nail, can grow into a new plant. Fresh stem material regenerates readily in a soil or water medium Japanese knotweed Photos
Photo of Japanese Kn...
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Japanese Knotweed
Japanese Knotweed
top of a young knotw...
unpeeled knotweed
my tasty victim
peeled knotweed stal...
Alien species
First earlies?
Snippets
The woody winter stems can take up to three years to decompose. Some of the problems caused by Japanese knotweed are...
* Damage to paving and tarmac areas
* Damage to flood defence structures
* Damage to archaeological sites
* Reduction of biodiversity through out-shading native vegetation
* Restriction of access to riverbanks for anglers, bank inspection and amenity use
* Reduction in land values
* Increased risk of flooding through dead stems washed into river and stream channels
Japanese knotweed news
Updated every 30 minutes
- Core protocol after antibiotics?
- Also saw your herb order recommendation in a previous post (Japanese knotweed, Cats Claw, Eleutherococcus, Andrographis). Thank you! ...
- Dumping threat to bluebells in wood
- We get old patio, paving stones, fencing and plants like Japanese Knotweed that we absolutely don't want in the wood." One visible effect has been the ...
- Trees and bushes dying after careless spraying
- By Andrew Brookes TREES and bushes in Sutton Bridge were wrongly sprayed with a chemical used to kill a Japanese Knotweed infestation, leaving councillors ...
- Meredith learns to fight off alien invaders
- Hayes said that Japanese Knotweed, Oriental Bittersweet, and Purple Loosestrife are the three worst upland invasive plants in Meredith, with knotweed as the ...
Related links
- Japanese Knotweed Alliance
- Japanese Knotweed Alliance
- Environment Agency - Japanese Knotweed Information
- Environment agency
- Defra, UK - Wildlife and Countryside - Non-native species
- DEFRA
- Japanese Knotweed (Fallopia Japonica) Control, Removal and Eradication throughout England, Wales and Scotland
- Wreford Limited provide a comprehensive japanese knotweed control or eradication service throughout the UK. Our services are designed to efficiently remove Japanese knotweed whilst providing a cost effective solution.
- Caledonia Environmental Ltd.
- Japanese Knotweed Consultants. Helping the world deal with the Japanese Knotweed.
Comments
cbosleeds wrote...
This is a beast of a Japanese knotweed resource - congratualtions on a very thorough article - thee is more Japanese knoweed info here: http://www.ecocontrol.co.uk/
Posted September 03, 2008
BYE!
Hope to see you again soon...
HILLANDGLEN 
