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Japanese Knotweed

Japanese knotweed in garden

What is Japanese Knotweed?

Japanese Knotweed (Fallopian Japonica) is a highly invasive weed that was brought to the UK by the Victorians in the 1800s, with the intention of introducing a new ornamental garden species. At the time it was considered a prized specimen plant. However, what these pioneers had not appreciated is that Japanese Knotweed is deeply invasive and will spread relentlessly; dominating native species.

Why is Japanese Knotweed a problem in the UK and Ireland?

Japanese Knotweed can grow by up to 8 centimetres a day, and is sufficiently strong enough to grow through faults in pipes or brickwork and voids in tarmac or concrete; causing damage to buildings, roads, driveways and gardens.

The roots of the plant can extend to 3 metres deep and many metres across, potentially growing into building foundations and drains – causing serious structural damage.

A professional and scientific approach to its eradication is vital if 100% success is to be guaranteed.


Think you could have Japanese Knotweed on your land? Click here to view images of Japanese Knotweed throughout the seasons.


Japanese Knotweed and the Law

Wildlife and Countryside Act (1981)

Japanese Knotweed is listed under Schedule 9 of the Wildlife and Countryside Act (1981) and is classified as an invasive species

Schedule 9, section 14 states that it is an offence to plant or otherwise cause the species to grow in the wild.

Section 14(2) states that “if any person plants or otherwise causes to grow in the wild any plant which is included in Part 2 of Schedule 9, he shall be guilty of an offence”

An offence under the Wildlife and Countryside Act 1981 can result in a criminal prosecution.

Environmental Protection Act (1990)

Japanese Knotweed is classed as “controlled waste” and as such must be disposed of safely at a licensed landfill site according to the Environmental Protection Act (Duty of Care) Regulations.

Soil containing rhizome material will regarded as contaminated and, if taken off site, must be disposed of at a suitably licensed landfill site and buried to a depth of at least 5 metres.

Section 33 of the EPA states that it is an offence to deposit, treat, keep or dispose of controlled waste without a license.

An infringement of the Environmental Protection Act can result in an unlimited fine.

Anti-Social Behaviour, Crime and Policing Act (2014)

Individuals and organisations failing to control Japanese Knotweed on their land can be issued with a notice under antisocial behaviour orders (ASBOs).

Penalties can range from an on-the-spot fine of £100, to prosecution and a fine of up to £2,500 for individuals and £20,000 for organisations.

Japanese Knotweed and Property Value

When it comes to the sale of what is likely to be your most valuable asset, Japanese Knotweed can cause a lot of problems and reduce the value of your asset by many thousands of pounds.

The presence of Japanese Knotweed is likely to deter viewings

Estate Agents have an obligation under consumer protection regulations to advise any potential purchaser of any material facts that could affect their decision to buy. The presence of Japanese Knotweed is considered as being “material” under these regulations.

The presence of Japanese Knotweed must be declared

There is now an obligation to disclose the presence of Japanese Knotweed during the pre-contact enquiries made by solicitors (this is on the TA6 Law Society Form). Failure to disclose could result in a legal claim of misrepresentation.

The presence of Japanese Knotweed can prevent mortgage offers from being made

The majority of UK mortgage lenders will not offer funds to buyers of a property with Japanese Knotweed UNLESS there is a Knotweed Management Plan in place from a reputable and professional eradication firm. Any works done also need to be identified within an Insurance Backed Guarantee (IBG).


Japanese Knotweed and Neighbouring Land

It is not just those wishing to sell property that are affected by the relentless growth of this insidious plant. Under the Anti-Social Behaviour, Crime and Policing Act (2014), individuals and organisations can be penalised or prosecuted if they fail to control the growth of Japanese Knotweed on their land.

In 2017, there was a landmark case in Cornwall where a Judge ruled that the owner of the land from where the Japanese Knotweed had spread had to pay damages to the owners of the neighbouring property, that had also developed an infestation, along with an order to employ a professional eradication firm to control, remove and eradicate the Japanese Knotweed.

This reinforcement of the legal precedent will have an increasing effect on Local Authorities, Housing Associations, Councils, commercial and private landlords, the Commercial Developer and the private homeowner. In short, any individual or company that owns land or property.

UPDATE JULY 2018: The Court of Appeal rules that Landowners entitled to damages for Japanese knotweed

“Landowners have a measured duty of care to ensure that Japanese Knotweed does not spread from their land, following the Court of Appeal decision in Williams v Network Rail Infrastructure Limited. Even in cases where no actual physical damage has been caused, the court decision opens up claims by neighbours for loss of amenity value due to the hazard created by the mere presence of the plant’s rhizomes under their property.”



Need some guidance?

Japanese knotweed growing in front of houses in London


Do you have Japanese Knotweed? Has your buyer’s mortgage been refused? TCM supply eradication solutions for homeowners.

Japanese knotweed rhizome


TCM provide science based solutions to a wide range of industries including construction, rail, road and the London Overground.

Howard Downer, MD of TCM Ltd


Howard Downer, AKA Dr. Knotweed, has over 20 years of experience as an Environmental Consultant and is regarded by his peers as one of the most knowledgeable people in the Japanese knotweed industry.

Follow Dr. Knotweed to hear of about the latest developments regarding Japanese knotweed and the implications of infestation.

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