Japanese knotweed and the law

Japanese Knotweed and The Law

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If you own or manage a property or land which is affected by Japanese knotweed, you are responsible for the control of the invasive weed. Failure to do so could lead to unwanted disputes, substantial fines, or even imprisonment.

There is a reported lack of awareness of the legal responsibility of homeowners to prevent knotweed from spreading, with only 36% knowing they could be sued and just 18% aware they could face prosecution. Japanese knotweed is NOT to be ignored. The information on this page is intended to give you some guidance on the laws relating to Japanese knotweed.

Japanese Knotweed Encroachment

Japanese knotweed encroachmentIf a property is found to have an infestation of Japanese knotweed on their land or Japanese knotweed within 7 metres, it is extremely difficult to secure a mortgage against the property. Therefore, Japanese knotweed doesn't have to be located within the boundary of your property for a surveyor to categorise your property from being at risk from Japanese knotweed.

If Japanese knotweed spreads from one property to another the relevant law is that of private nuisance. A private nuisance is an act or omission which is an interference with, disturbance of or annoyance to a person in the exercise or enjoyment of his ownership or occupation of land.

Encroachment from Railway Lines

Increasingly, we're contacted by homeowners that suspect they have knotweed encroachment from railway lines close to their property. Not only does this cause for concern for the buildings on their property, but the invasive nature of the weed can cause loss of enjoyment of the garden. We have a vast amount of experience in dealing with these types of cases. Contact us using the form on this page and we'll call you to discuss your situation and inform you of the options available to you.

Williams and Waistell v Network Rail

In July 2018, the case of Williams and Waistell v Network Rail was heard at the Court of Appeal, as Network Rail had appealed against the original verdict. The Court of Appeal unanimously upheld the decision of the Recorder but held that the claimants cannot claim in private nuisance merely because of the diminution in the properties' market value because of lender caution in such situations. The claimants can claim, however, in respect of the encroachment of Japanese knotweed rhizomes because they have diminished the claimants' ability to enjoy the amenity and utility of their respective properties. The Japanese knotweed and its rhizomes presence impose and immediate burden on landowners who face an increased difficulty in their ability to develop, and in the cost of developing, their land, should they wish to do so, because of the difficulties and expense of eradicating Japanese knotweed from affected land. In this way, Japanese knotweed can fairly be described as a natural hazard that affects landowners' ability fully to use and enjoy their property and, in doing so, interferes with the land's amenity value.

Prevent the Spread of Knotweed

If a landowner has knotweed growing in the garden of his property he should make every effort to control the knotweed and prevent this invasive weed from spreading onto a neighbouring property and if he fails to do this he could be held responsible for the damage caused by the encroachment. If you are able to prove that your property is affected by knotweed because of encroachment the landowner of the adjacent property could be held responsible.

Giving Notice to Your Neighbour

If you do wish to pursue your neighbour, the individual or organisation responsible for the adjoining land must be given the opportunity to deal with the nuisance (knotweed). It is therefore important that you put your neighbour(s) on notice in writing as soon as you become aware of encroachment and that you state what action you require the landowner to take and by when.

In these circumstances, you should ask your neighbour to effectively treat the knotweed not only on their land but also on your property in order to solve the problem and ideally the remedial action they choose should include a suitable guarantee. The letter should also explain the likely consequences if they choose to ignore the notice.

To help you take this further we can undertake a specialist survey of the knotweed. Ideally, we would need access to all of the affected garden(s). The survey will provide you with a written document that will accurately identify the knotweed and its location. If it is clear that the knotweed in your garden is encroachment from an adjoining property we will confirm the encroachment and you will be able to provide this as evidence to the neighbouring landowner.

Find out more about our Japanese Knotweed Survey here.

Encroachment Legal Rights

Should the neighbour not comply with the notice, a claim for "nuisance for encroachment" can be pursued through legal channels.

Japanese Knotweed and ASBOs

Japanese knotweed ASBOThe government has reformed the Anti-social Behaviour, Crime and Policing Act 2014 so that community protection notices can be used against individuals who are acting unreasonably and who persistently or continually act in a way that has a detrimental effect on the quality of life of those in the locality. The Act does not explicitly refer to Japanese knotweed or other similar invasive non-native plants, as the new anti-social behaviour powers are intended to be flexible. However, frontline professionals can stop or prevent any behaviour that meets the legal test in the powers.

Unreasonable Conduct

Under the Act a Community Protection Notice (CPN) can be used to require someone to control or prevent the growth of Japanese knotweed or other plants that are capable of causing serious problems to communities. The test is that the conduct of the individual or body is having a detrimental effect of a persistent or continuing nature on the quality of life of those in the locality and that the conduct is unreasonable. Under section 57 of the Act, “conduct” includes “a failure to act”. A CPN could therefore be used to require someone to control or prevent the growth of Japanese knotweed or other plants that are capable of causing serious problems to communities.

Fixed Penalty Notice

This means if an individual, or organisation is not controlling Japanese knotweed or other invasive plant and could be reasonably expected to do so, the CPN could be used after a mandatory written warning has been served beforehand to get them to stop the anti-social behaviour. Breach of any requirement of a community protection notice, without reasonable excuse, would be a criminal offence, subject to a fixed penalty notice. On summary conviction, an individual would be liable to a fine not exceeding £2,500. An organisation, such as a company, is liable to a fine not exceeding £20,000.


Knotweed misrepresentationPaperwork in conveyancing, when selling a house, includes a form called the Law Society Property Information Form, or a "TA6". This form ensures that the solicitor asks whether the property is affected or has ever been affected by Japanese knotweed.

Whilst it's tempting not to declare certain information which might put prospective buyers off, honesty is always the best policy because you run the risk of being sued in the future if the information you provide is intentionally misguiding. The question of whether a property is affected by Japanese knotweed was added in 2013. This is because mortgage lenders want to know if the property has knotweed growing on it, or close to it.  If it does have knotweed, they usually ask for evidence that there is a Knotweed Management Plan (KMP) in place.

Answering the Japanese Knotweed Question

The question on the form reads thus:

“Japanese knotweed is an invasive plant that can cause damage to property. It can take several years to eradicate.” It then asks sellers: “Is the property affected by Japanese knotweed?”

To which there are three possible answers:

If the answer is yes the form asks the seller to state whether there is a Japanese knotweed management plan (KMP) in place and if so to supply a copy. From a conveyancing perspective, this is clearly the most straightforward response. A solicitor representing the buyer should ensure that the KMP is adequate. A specialist knotweed contractor will be required to treat the affected areas and the long term management plan should clearly detail the record of works carried out and to be carried out.

Sellers should provide this to the purchaser’s solicitors, who in turn should enquire to see if it can be transferred to their client. The KMP must be fit for purpose and provide a long term guarantee and for some lenders may need to be backed by insurance.

Not Known
This response can serve to trigger alarm bells when reviewed by the purchaser’s solicitors. A request, via an enquiry, is likely to be made for further information and perhaps a specialist knotweed survey. The ‘not known’ answer is arguably the most honest for the majority of sellers, but in reality, it should serve only to prompt the buyer’s solicitors to probe for further information. The seller may add a caveat along the lines of ‘buyer should rely on their own survey’.

For the vast majority of sellers, the selected response will be ‘no’. The seller may add a caveat along the lines of: ‘as far as I am aware’ to a response of ‘no’. This may reflect the fact that knotweed can be hard to spot in its early stages and most property owners are not horticultural experts. However, if a seller, based on the best of their knowledge, answers ‘No’, and it subsequently transpires that the plant is present, then the buyer may pursue the seller for compensation.

Knotweed Management Plan is Paramount

The presence of knotweed does not automatically prevent a mortgage from being obtained, with a case by case basis approach often adopted. Evidence of a suitable Knotweed Management Plan is paramount. Whilst it might be a shock to find out that the property you are trying to sell has knotweed, or indeed, the property you intend to buy is affected, there are treatments available to manage the infestation and the Knotweed Management Plan is the key.

Misrepresentation Legal Rights

When buying a house, the person you are buying from is required to disclose if the property is affected by Japanese knotweed. If you have bought a house that's affected by Japanese knotweed, and you are able to show the seller knew about Japanese knotweed on the property, you can sue the seller.

Loss of Property Value

Loss of Property Value due to knotweedIf a property is found to have an infestation of Japanese knotweed on their land or Japanese knotweed within 7 meters, it is extremely difficult to secure a mortgage against the property.

As a result, a property affected by Japanese knotweed, whether it is in their boundary or within 7 meters, loses value. This is called diminution of value. If you are successful in bringing a Nuisance Claim against a defendant, then it may be possible to include a claim for diminution of value in any settlement.

Professional Negligence

If you purchased a property and paid for a professional survey to be carried out and the surveyor did not pick up the presence of Japanese knotweed, you may be able to bring a claim against the surveyor for professional negligence. If you are able to show that the surveyor should have noticed the Japanese knotweed, you can make a claim.

Japanese Knotweed Legal Help

As experts in the field of Japanese knotweed we can help with legal claims regarding Japanese knotweed.

Disposal of Japanese Knotweed

Disposal of KnotweedThe Government website has guidance called "Prevent Japanese knotweed from spreading". It states:

"You must dispose of Japanese knotweed waste off-site by transferring it to a disposal facility that’s permitted, e.g. a landfill site that has the right environmental permit."

"You must prevent Japanese knotweed on your land from spreading into the wild and causing a nuisance. You could be fined up to £5,000 or be sent to prison for up to 2 years if you allow contaminated soil or plant material from any waste you transfer to spread into the wild."

This means if you cut back knotweed or dig it up and take it to your local waste and recycling centre that does not have the right environmental permit, you could be fined or sent to prison.

The Government website continues to state:

"You must not:

  • dispose of Japanese knotweed with other surplus soil
  • sell soil contaminated with Japanese knotweed as topsoil

You can only reuse knotweed-contaminated soils after treatment, on the site where they were produced."

At Japanese Knotweed Ltd, we are fully equipped and highly trained to deal with Japanese knotweed infestations. Our team of field technicians have the relevant qualifications and experience to treat Japanese knotweed in a professional and legally compliant manner.  If you suspect you have knotweed on your property, call in Japanese Knotweed Ltd, your local knotweed experts today: 0333 2414 413.

Wildlife and Countryside Act 1981

The Wildlife and Countryside Act 1981 is the primary legislation which protects animals, plants, and certain habitats in the UK. It's worth noting, however, that since the passing of this Act in 1981, there have been various amendments to the text of the Act and the species listed in the schedules. Read more about the Wildlife and Countryside Act 1981.

Environmental Protection Act 1990

The Environmental Protection Act 1990 (EPA) is an Act of the Parliament of the United Kingdom that as of 2008 defines, within England and Wales and Scotland, the fundamental structure and authority for waste management and control of emissions into the environment. This Act governs the disposal of controlled waste, such as Japanese knotweed. Read more about the Environmental Protection Act 1990.

Environmental Protection (Duty of Care) Regulations 1991

This Act exists to ensure responsibility is taken by the producers of waste (such as Japanese knotweed) for managing their waste and avoiding harm to human health or the environment.

The Act aims to reduce or eradicate harmful acts of waste crime, such as fly-tipping. The Duty of Care incorporates a responsibility on anyone who produces, imports, carries, keeps, treats or disposes of controlled waste to ensure it is only ever transferred to someone who is authorised to receive it. Read more on The Environmental Protection (Duty of Care) Regulations 1991.

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