Japanese Knotweed – Getting to the root of the matter

28 July 2022

Japanese knotweed is an invasive plant and one of the UK's most pernicious weeds. It reproduces and spreads throughout Britain via knotweed, contaminated soil, and rhizome fragments. Since 1850, when it was introduced into the UK by the Victorians as a bamboo-like ornamental plant, knotweed has spread across the UK, with areas of high concentration found in Bristol, Nottingham, Rotherham, and Glasgow.

Seemingly just a weed from above the ground, it has very strong roots which can grow up to 10 feet deep and can cause severe damage to concrete, road surfaces and the foundations of properties. Therefore, it has the potential to have a devastating financial impact.

As such, if it is found at or near to property, it will adversely impact the property’s value. Mortgage companies will be reluctant to lend, and it may cause negotiations on the sale of the property to break down.

Japanese Knotweed is a menace with the potential to wreak havoc and property. If found on a property, it needs to be treated carefully and by a specialist.

Yet, this treatment can be expensive. It’s not something which a property owner should try to get rid of on their own without specialist advice. In fact, mortgage companies will insist on an expert being involved.

Find government guidance - How to stop Japanese knotweed from spreading

Disputes with neighbours

If Japanese knotweed on a neighbour’s land is having a detrimental impact, then it may be possible to bring a nuisance claim. It is worth noting that there does not necessarily have to be physical damage to property to bring a nuisance claim.

The fact that Japanese knotweed is present may be enough to bring a claim, on the basis that it is likely to have a detrimental impact on the enjoyment of the land due to the risk of future damage to buildings.

Furthermore, a nuisance can be caused by inaction or omission as well as positive activity. This means that failing to take reasonable steps to bring a Japanese knotweed problem to an end may give grounds for a claim.

If a claim is successful, the court may order the neighbour responsible for the Japanese Knotweed to pay damages to the claimant for the cost of treatment and of obtaining an insurance-backed guarantee.

Criminal law considerations

There are a few things to consider when it comes to Japanese Knotweed and staying on the right side of the law.

Allowing Japanese Knotweed to grow in the wild is a criminal offence (14(2) Wildlife and Countryside Act 1981). 

A garden is not in the wild, and it is not an offence to have it on your private property, but the fact there are criminal sanctions highlights just how seriously the problem is taken by legislators.

Failure to prevent it from becoming a nuisance to neighbouring properties or land means you could face a risk of being prosecuted under the Anti-social Behaviour, Crime and Policing Act 2014.

Claims relating to the buying and selling of residential property

When a solicitor is acting for a buyer, as standard they will ask the seller to confirm whether the property is affected by Japanese Knotweed. If, after the transaction has been completed, the buyer notes the presence of knotweed and believes that the seller misrepresented the position before the transaction was completed that may give rise to a claim.

Similarly, if a buyer’s solicitor did not ask the question about the presence of knotweed or failed to inform their client that the seller had answered to say that there was a Japanese knotweed issue then this can give rise to a negligence claim against the buyer’s solicitor (by the buyer). I have personally dealt with a claim against a solicitor where they failed to inform their client the seller had flagged that Japanese knotweed was an issue.

If a property is being bought with a mortgage, then the bank will require that a surveyor inspects the property. If that surveyor has given incorrect advice about Japanese Knotweed, such as whether it is present at all or about the scope of the knotweed then that could result in a negligence claim being brought against that surveyor by the bank or by the purchaser.


As stated above, it is possible to seek a claim for damages for the cost of treatment in nuisance claims. In a negligence claim against a profession, typically the claim would be for diminution in value of the property. 

Even applying to the court for an injunction may be appropriate in some circumstances.

Key takeaway point

When it comes to Japanese Knotweed, you must act fast. This is because, just as the weed is very invasive and grows rapidly, so does the potential legal battle.

It’s worth remembering that most disputes settle before trial and an experienced solicitor will aim to resolve the dispute as quickly as possible and, if possible, without involving the court.

This article is for information purposes only and should not be relied upon in place of legal advice.

© Melissa Worth, July 2022

The Dispute Adviser

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