Japanese Knotweed Identification UK

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Japanese knotweed, or Fallopia Japonica, is a member of the Buckwheat family and has various derivatives including Giant knotweed and Himalayan knotweed.

Japanese knotweed is an invasive plant that can be found throughout the UK. Japanese knotweed identification can be difficult, as the plant can look similar to other plants. However, there are some key identifying features of Japanese knotweed that can help you determine whether or not a plant is Japanese knotweed. Japanese knotweed is a herbaceous perennial plant, which means it dies back during winter and regrows from ac rhizome (underground stem)

It was introduced to the UK in the 1800s as a garden plant by the Victorians and has since spread to railways, riverbanks, farm hedges and industrial sites.

Japanese Knotweed Herbicide Treatments

Japanese Knotweed throughout the year


The first signs of Japanese knotweed growth are distinctive red and purple shoots. These are often accompanied by rolled back leaves which grow rapidly from the stored nutrients in the rhizome.


The stem resembles bamboo, though more green in colour with purple speckles. Inside, the stem has distinctive chambers that retain water and nutrients.


As the first frost appears, the plant’s leaves turn brown. During this period Japanese knotweed withdraws back into its rhizome.

The canes lose colour and turn into woody stalks which can take years to decompose.

New shoots can be found growing through the dead canes in the early Spring.

Japanese knotweed from January to March

Japanese Knotweed in January

Japanese Knotweed in February

Japanese Knotweed in May

Japanese Knotweed in June

Japanese Knotweed in July

Japanese Knotweed in November

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Japanese Knotweed and the Law

Japanese knotweed is governed by numerous laws and acts concerning the way in which it is treated and disposed of, due to its damaging ability to spread aggressively if mishandled.

United Kingdom



Section 14(2) of the Wildlife & Countryside Act 1981 states that “If any person plants or otherwise cause to grow in the wild any plant which is included in part 2 of schedule 9, he shall be guilty of an offence.” Japanese knotweed is listed in this schedule and included within this legislation. Anyone convicted under section 14 of this act is liable to a fine of £5000 and/or 6 months imprisonment, or 2 years and/or an unlimited fine on indictment.



This act states that waste is recovered and disposed of “without endangering human health and without using processes or methods which could harm the environment and in particular risk to water, soil, plants or animals or cause nuisance through noise, or odours or adversely affecting the countryside or places of special interest.” This has many implications for the treatment of Japanese knotweed including most of the treatment methods, and failure to use a licensed operative could leave you liable to prosecution.



This extensive legislation covers all areas of ‘controlled waste’ which includes Japanese knotweed soil and plant material. Failure to follow the guidelines set out by this legislation, including not having the correct licences to treat Japanese knotweed, can lead to prosecution.



Although Japanese knotweed is not covered by this legislation specifically, when certain residual herbicides are used, it then becomes hazardous and falls under this legislation. Failure to abide by this legislation will lead to prosecution ..

Ireland and Northern Ireland



It is an offence to plant or otherwise cause to grow in the wild Japanese knotweed or any other invasive plant listed in Part II of schedule 9 to that Order. Furthermore, Sections 52(7) and (8) of the Wildlife Act, 1976, as amended, make it an offence to plant or otherwise cause to grow in a wild state exotic species of plants.



Any person who plants, disperses, allows or causes to disperse, spreads or otherwise causes to grow Japanese knotweed or any of the other invasive plants listed in the Third Schedule of the European Communities (Birds and Natural Habitats) Regulations, 2011 (S.I. No. 477 of 2011) shall be guilty of an offence.

Japanese Knotweed Identification UK

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