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Japanese Knotweed, Fallopia japonica


Short description of Fallopia japonica, Japanese Knotweed

Herbaceous perennial, with stems typically about 2m tall and an extensive system of rhizomes. It has large, roughly triangular leaves with truncate (not cordate (heart-shaped)) bases.

Description of Fallopia japonica, Japanese Knotweed status in GB

Japanese knotweed is an invasive non-native weed, mainly in urban areas where it is considered a nuisance in property development, because plants regrowing from rhizomes can come up through gaps in flooring in conservatories and patios.

Habitat summary: Fallopia japonica, Japanese Knotweed

Disturbed habitats in urban areas, by water courses, canals and on waste ground, usually in full sunshine. It is shade tolerant and occasionally invades woodland. Long established stands by rivers tend to have a similar vernal ground flora to W6 Alnus glutinosa woods, with F. japonica providing the canopy layer during the summer months.

Overview table

Environment: Terrestrial
Species status: Non-Native
Native range: Eastern Asia
Functional type: Land plant
Status in England: Non-Native
Status in Scotland: Non-Native
Status in Wales: Non-Native
Location of first record: v.c.41
Date of first record: 1886

Distribution map

GB Distribution from BSBI

Author's name:

Helen Roy and Alice Hiley

Last updated:

August 26th 2016

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Thin strip of image show tree trunk and bark