Do You Have Japanese knotweed on Your Property? What does the law say about Japanese knotweed?

Every garden has weeds, what makes Japanese knotweed such a big deal?

Japanese knotweed is particularly threatening due to the way it can rapidly spread and even cause damage to buildings and structures. If left unchecked, even a small little root (rhizome) can quickly turn into a big plant. 


A weed that can cause structural damage? Really? The scary thing about Japanese knotweed is that it is strong enough to grow through cracks in concrete, and even roads.


This is why there are strict laws to prevent the spread of this harmful invasive species, and why you should be extremely cautious when purchasing a property with a Japanese knotweed infestation. The value of even a highly desirable property can take as much as a 20% knock if Japanese knotweed is present and not treated appropriately via a reputable specialist company.


In this article, we look at the laws designed to curb the spread of Japanese knotweed and how they affect property owners, the community and prospective property buyers.


Japanese knotweed infestation is a big problem in the UK and there are several acts and regulations that deal with this invasive plant species, including the Wildlife and Countryside Act of 1981, the Environmental Protection Act of 1990, the Environmental Protection (Duty of Care) Regulations of 1991, the Town and Country Planning Act of 1990, as well as Northern Ireland’s Wildlife Order and Scotland’s Town and Country Planning Act of 1992. 

Together, these acts and regulations protect the plants, animals and natural habitats in the UK, stipulate how waste such as Japanese knotweed, should be disposed of, and provide a framework within which those not complying with the law can be served notices and prosecuted.


One of the most common measures against Japanese knotweed is the Property Information Form, or TA6, a document used by sellers to give prospective buyers important information about the property so that they can make an informed decision. This includes things like parking, alterations to the property, insurance and environmental matters including energy efficiency and the like. The TA6 form addresses concerns regarding Japanese knotweed with the following question:

Is the property affected by Japanese knotweed?

The form provides three possible answers to the question, namely ‘yes’, ‘no’ or ‘not known’. The answers may seem simple, but each answer to “the Japanese knotweed question” carry certain responsibilities — let’s take a look:


If you as a seller answer ‘yes’ to the Japanese knotweed question on TA6, you will be asked if you have a Japanese knotweed Removal Plan (KMP) in place to remove Japanese knotweed from your property and the adjacent 3 meters beyond the property boundary. Should you have a KMP, you will be required to provide documented proof. The document should clearly indicate the work being carried out by a specialist contractor at present, as well as future work that may be required.


The buyer’s solicitor should inspect the KMP document to determine whether the measures mentioned are and will be adequate to remove Japanese knotweed from the property. Since most KMPs are ongoing, the buyer’s solicitor should investigate whether it is possible to transfer the KMP to the buyer. The KMP serves as a long-term guarantee to potential lenders of the removal and ultimate removal of Japanese knotweed on the property in question. Some lenders may require additional insurance as an additional financial safety measure. All treatment programmes or remediation work should be accompanied by a 10-year Insurance Backed Guarantee.


In the past, “no” was the answer of the majority of property sellers, with a simple caveat of “to my knowledge”. However, the changes to TA6 seen above has made it extremely difficult for sellers to answer “no” unless they are 100% certain that there is no Japanese knotweed present on their property and within 3 meters outside of the property boundary. Legally a “no” answer entitles a buyer to take legal action against the seller for financial compensation should Japanese knotweed be found on the property post-purchase.

Not known

In lieu of the strict requirements of a “no” answer, the safest answer for sellers is “not known”. This may prompt the buyer’s solicitor to require a specialist to inspect the property and carry out a Japanese knotweed Survey. Conditions of sale often require that these inspections are to be performed at the seller’s expense.


A private nuisance

The Royal Institute of Chartered Surveyors classify any Japanese knotweed found within 3 meters of the property boundary as high risk and could make it extremely difficult to secure a mortgage or loan.


In fact, if the Japanese knotweed on a property spreads to a neighbouring property, it could be seen under law as a private nuisance and can be prosecuted as such. It should be noted that the law concerns the enjoyment and use of a property and not the diminishing effect that Japanese knotweed can have on the value of the property.

Curb the spread

It is the responsibility of a landowner to ensure that Japanese knotweed does not grow on the property. Should they discover Japanese knotweed, every effort should be made to remove the knotweed and its roots from the property and keep it from spreading onto adjacent properties. Failure to do so may result in legal action from the adjacent property owner to recover costs in relation to the law mentioned above.

Approach your neighbour

Should you notice encroachment of Japanese knotweed from an adjacent property, you may contact the landowner of the property via written notice and give them the opportunity to deal with the situation. The notice must include a timeframe, the remedial action you want the relevant landowner to take on their property, as well as adjacent properties. The notice should also detail the consequences of ignoring the notice and/or failure to implement the suggested actions.


If you are unsure of the origin of the Japanese knotweed on your property, you can call us to complete an inspection of your and adjacent properties. The report can serve as evidence to the landowner in question. It must be noted that without photographic evidence over time, it can be very difficult to establish where a Japanese knotweed infestation started.


If no action has been taken by the neighbour to remove and manage Japanese knotweed from their and/or your properties, you can pursue legal action through a claim of “nuisance for encroachment” via a solicitor.


Japanese knotweed problem is a serious environmental threat in the UK and failure to act when traces of Japanese knotweed is found on your property may be seen as anti-social behaviour, and the Anti-social Behaviour, Crime and Policing Act of 2014 provides the legal scope to address this type of behaviour.

Acting unreasonably

While the Act does not explicitly mention Japanese knotweed, the species can cause such damage that the quality of life and enjoyment of facilities by individuals can be greatly reduced. When someone ignores or refuses to deal with Japanese knotweed on their property, their behaviour can be seen as ‘unreasonable’ under Section 57 of the Act and a Community Protection Notice (CPN) can be issued in an attempt to rectify the behaviour and control the growth and spread of Japanese knotweed in the community. A CPN carries certain requirements that legally need to be adhered to.

Fines & Criminal prosecution

Prior to issuing a CPN, the individual or organisation in question must first be served by a written warning. Should the written warning not result in a change of behaviour (by implementing measures to remove and prevent the spread of Japanese knotweed on and from the property), a CPN can be served on the property owner.


Failing to comply with the requirements set by the CPN, and without any reasonable excuse, is deemed a criminal offence, the penalty for which is a fine of up to £2,500 for individuals and up to £20,000 for organisations.


When dealing with Japanese knotweed, you shouldn’t just take care to remove the plant and all its roots, but also how you dispose of it. The Government has specific guidelines for disposing of Japanese knotweed to reduce the risk of spreading.


The guidelines stipulate that Japanese knotweed should be disposed of off-site by taking it to a waste disposal facility with the appropriate permits. Japanese knotweed should not be disposed of with other surplus soil.


Further, soil contaminated with Japanese knotweed may not be sold as topsoil, and contaminated soil may only be reused once it has been treated on the site where the soil is produced.

Failure to prevent Japanese knotweed from your land from spreading into the wild due to improper waste transfer is a serious offence and can carry a fine of up to £5,000 or up to 2 years in prison.


Japanese knotweed poses a serious threat to the natural fauna and flora in the UK and can greatly impact the structure of buildings and the enjoyment of property and facilities. The Government has put in place certain laws and regulations to prevent Japanese knotweed from spreading, thereby giving you certain legal rights.


Remember, when you are buying a house, the seller is legally obliged to disclose whether there is Japanese knotweed present on the property. If not, and you find traces of Japanese knotweed on the property, you are entitled to sue the seller for financial damages.


What’s more, if you have paid a professional surveyor to inspect the property for Japanese knotweed and they have found none, you may make a claim of professional negligence against them should you find signs of Japanese knotweed. However, such a claim can only be made if you are able to prove their negligence.


As a seller, providing full transparency regarding Japanese knotweed on your property is critical to avoid future legal action. If you find any traces of Japanese knotweed or suspect that there may be Japanese knotweed present, you should take immediate action by hiring specialists to inspect and treat your property for Japanese knotweed. The sooner you catch it, the easier it is to manage and the more peace of mind it will give you in the long run.

Looking for professional help in removing Japanese knotweed?

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Looking for professional help in removing Japanese knotweed?

Find out the options you have removing Japanese knotweed supported by our 10-Year Insurance Backed Guarantee.