Japanese Knotweed Law & Legal Advice

By Paolo Martini on 11th February 2019 (updated: 6th January 2021) in News

The government has introduced a number of Japanese knotweed laws and regulations surrounding the control, growth and transportation of Japanese Knotweed in order to protect homeowners, businesses and the environment alike. These laws have been put into legislation slowly over the years as a reaction to the growing spread of invasive plant species in the UK.

Japanese knotweed arrived in the UK in 1850, and since then has spread throughout most of the country. There are serious legal risks inherent with having Japanese knotweed growing on your land so it’s best to get a handle on it sooner rather than later, otherwise you may find yourself at the receiving end of a fine.

Introduced from Japan in 1850, Japanese Knotweed is one of the most pernicious weeds in the UK. In its native habitat, Japanese Knotweed is a pioneer species found typically on Volcanic Iarva .Reproduced rapidly via tiny fragments of its rhizome, the weeds of Japanese Knotweed can grow up to 10cm a day and in just 10 weeks its stems can reach 3-4 metres in height.

Understanding your legal responsibilities in regards to knotweed growing on your land is crucial should you wish to avoid an unexpected date in court or a run-in with your local council.

How dangerous is Japanese knotweed?

Although Japanese knotweed is not poisonous or directly “dangerous” to people, the continued spread of Japanese Knotweed poses a threat to the environment, homeowners and business owners alike.

This hardy, invasive plant can grow rapidly throughout the warmer months, and then die back in winter, remaining dormant underground in a network of rhizomes, before emerging to spread even further. Japanese knotweed stifles native species and reduces house prices. Choosing to ignore its presence on your land can often prove to be a costly mistake.

Evidence from a recent government report suggests that if a knotweed infestation remains untreated then losses of up to 10% can be incurred. Even if the knotweed is treated and removed, losses can still be between 6-9%.

Related: What Does Japanese knotweed Really Do?

Laws controlling Japanese knotweed

Japanese knotweed New legislation

Under new Japanese knotweed legislation, Homeowners failing to control Japanese Knotweed on their property can be prosecuted and fined up to £2,500. This is due to new Home Office rules and regulations relating to anti-social behaviour being introduced in 2014 that include new laws around Knotweed amongst other invasive species such as the Himalayan Balsam and Giant Hogweed.

These new Japanese knotweed laws have been added to pre-existing laws relating to Anti-Social Behaviour Orders, and join older legislation such as the Environmental Protection Act 1990 and Wildlife and Countryside Act 1981.

Japanese knotweed anti-social behaviour law

In 2014, a decision was made to include the negligent cultivation of invasive plants such as Japanese Knotweed into the remit of the Anti-social Behaviour Crime and Policing Act 2014. Under the powers of this act police and local council authorities have the power to issue individuals and businesses with Community Protection Notices.

These notices are only reserved for those who persistently or continually act in a way that has a detrimental effect on the quality of life of those in the locality.

This notice could require the recipient to make reasonable efforts to remove the knotweed from their property or prevent the knotweed from returning. Failure to meet the requirements of this notice, without a reasonable excuse, could be treated as a criminal offence making the recipient liable to a fixed penalty notice or prosecution, which could lead to a further hefty fine.

Environmental Protection Act 1990 (EPA 1990)

Besides the Anti-social Behaviour Crime and Policing Act 2014, the main legislation that identifies and controls Japanese knotweed is the Environmental Protection Act 1990 (EPA 1990) and the Wildlife and Countryside Act 1981 (WCA 1981).

The EPA 1990 sets out the appropriate methods of removing, transporting and disposing of ‘controlled waste’, defining this as any soil or plant materials contaminated with Japanese knotweed that you discard, or are planning on discarding. The Act makes it an offence to deposit any contaminated soil in an irresponsible fashion. In short, if you have knotweed on your land and you’re looking to dispose of it, you’ll need to follow the correct procedure should you wish to avoid a hefty fine.

Wildlife and Countryside Act 1981

The EPA 1990 is supported by the Wildlife and Countryside Act 1981 which states that ‘if any person plants or otherwise causes to grow in the wild any plant which is included in Part II of Schedule 9, he shall be guilty of an offence’. Japanese knotweed is listed as one of these plants in Schedule 9, offenders may face a £5000 fine and/or 6 months imprisonment, or 2 years and/or an unlimited fine on indictment. These may sound like heavy penalties, but it serves to demonstrate how seriously the law treats the spread of Japanese knotweed and is intended to deter citizens from giving this plant free reign to grow on their land.

How to tell if you have Japanese knotweed

Although it’s possible to confuse Japanese knotweed with a number of other common plants found in England, there are a handful of tell-tale signs that should tell you if you’re dealing with an infestation or not. Look for broad, green, shield-shaped leaves during the summer, attached to reddish hollow stems, similar to bamboo. During the winter, these stems appear to die off, becoming brown and brittle.

Related: How To Identify Japanese Knotweed

Is it illegal to have Japanese knotweed?

Japanese knotweed is classed as a controlled plant under the Wildlife and Countryside Act 1981 section 114 (2) (WCA 1981). It is not illegal for you to have Japanese knotweed on your property, but it is against UK law to cause or allow the plant to spread in the wild. You can be prosecuted or given a community protection notice for causing a nuisance if you allow it to spread onto anyone else’s property.

You will not be seen to be breaking the law until Japanese knotweed from your land spreads into another’s property or onto public land. As this plant is such a fast grower, it is usually only a matter of time before this happens and your troubles multiply.

Should you wish to legally build on land with Japanese knotweed then you will need to follow a few steps, to ensure that you’re not held liable years down the line. It’s important that plant is taken into consideration in the planning process, and that every effort is made to remove the plant and prevent it from further spreading.

What should I do if I find Japanese knotweed?

If you find Japanese knotweed on your land then you should take care to isolate the area and establish how much of your property has been affected by the plant. The next step is to determine where the plant came from and the extent to which the plant affects the property.

The best way of doing this is by getting a professional evaluation of the Japanese knotweed. A professional evaluation and survey will be able to answer the questions that you have and give you an idea of the actions that you’ll need to take to get rid of the infestation.

Is Japanese knotweed notifiable?

It is not an offence to have Japanese knotweed on your land and it is not a notifiable weed. Allowing Japanese knotweed to spread to neighbouring properties may be viewed as a private nuisance under common law, but this would be a civil matter. The Environment Agency is responsible for regulating waste.

Do I have to declare Japanese knotweed?

In the event that you discover an infestation on your land, you are not legally required to declare Japanese knotweed to the authorities. Although it is illegal to allow the plant to spread outside of your land, you are not required to declare the presence of Japanese knotweed to your neighbours or the local authorities.

If you are selling a property with Japanese knotweed then you should declare its presence openly with any prospective buyers and your estate agent. A Japanese knotweed specific question is included on most pre-contract enquiry questionnaires, which are based on the Law Society’s TA6 Form. If you choose to not answer truthfully on this questionnaire then a prospective buyer could sue you under the Misrepresentation Act.

Similarly, if you have bought an infested property with the understanding that no Japanese knotweed should be present on the land, you may be able to seek legal recourse against a seller who has lied about Japanese knotweed.

How and who do I report Japanese knotweed to?

You do not need to report the presence of Japanese knotweed on your land, however, should you wish to voluntarily declare your Japanese knotweed or report an infestation on public land, then you can do so by visiting the Non-native Species Secretariat website.

In the case where you have spotted Japanese knotweed encroaching on your land, but are yet to find the plant on your property, then your first action should be to inform the owner of the land about the infestation.

It’s often the case that Japanese knotweed is spread by gardeners, or construction workers who do not dispose of contaminated soil in the proper fashion. According to the Government, anyone seeking to get rid of their Japanese knotweed must use a registered waste carrier and a suitable disposal site. You can report those not abiding by these practices to your local authority.

Related: What to do if you’ve found Japanese knotweed on your property

Reporting Japanese knotweed to a local council

In the eventuality where an informal conversation has not yielded any results, you can start to take the necessary steps to report Japanese knotweed infestations to your local authority.

In order for a landowner to be considered to be persistently acting in a way that is detrimental to the quality of life to those in the locality (as it’s laid out in the Anti-social Behaviour Crime and Policing Act 2014) it must be proved that the individual has not taken reasonable steps to remove the infestation.

You will need proof that you’ve formally notified the land owner of the infestation (a letter or an email) before you can appeal to your local council for a Community Protection Notice.

I’ve bought a house with Japanese knotweed. What should I do?

If you’ve discovered Japanese knotweed on your own property then you’ll have a few options open to you regarding remunerations, depending on the context of your discovery of the infestation. Unfortunately, it’s unlikely that your home insurance will cover Japanese knotweed, so you will not be able to rely on it to financially support the removal of the Japanese knotweed or any damage caused to your home.

In the event that you have discovered knotweed on a property that you have purchased after a survey or TA6 property form stated otherwise, then you may be able to claim against the property surveyor or the previous owner of the property for the costs of the knotweed treatment. In the case where you have bought a property with the knowledge of the infestation then you will be liable for the costs of treatment.

Related: What to do if you’ve bought a property with Japanese knotweed

My surveyor missed the Japanese knotweed – can I do anything about it?

Property surveyors are not infallible, their mistakes can lead to buyers purchasing properties under the impression that their home is free of faults, when in fact the opposite is true. The presence of Japanese knotweed can lead to a home being devalued by up to 5% which can be a difference of thousands of pounds for homeowners. RICS surveyors should keep up to date with the current guidelines in relation to invasive plants if they miss Japanese knotweed on a survey then they may be sued for professional negligence.

Related: Has your surveyor missed Japanese knotweed?

What to do if there is Japanese knotweed encroaching from adjoining land

The legal remedy for knotweed spreading onto your land from adjoining land can be found in civil nuisance. To bring a successful claim, the claimant needs to demonstrate that the knotweed originated from the adjoining land, and that the knotweed is causing the claimant owner “nuisance”.

Despite the dangers of Japanese knotweed being well publicised, it’s still the case that landowners turn a blind eye when they have an infestation on their property. This inevitably leads to disputes with neighbours who are uncomfortable with having Japanese knotweed at such a close distance from their house.

Homeowners can often be placed in a difficult position where they’re aware that a knotweed infestation is close to their borders, but feel powerless to stop it spreading onto their own property.

Discovering the source of a Japanese knotweed infestation is key to determining what party is at fault. If it can be proven that the knotweed has entered from a neighbouring property then you should be able to claim for the costs of the removal of the plant.

This precedent has been set in cases involving both individuals and large organisations, so whether you’re dealing with Japanese knotweed on council land or from a next door neighbour, you should be able to claim for the treatment of the infestation.

What to do if a neighbour has Japanese Knotweed

If you have discovered knotweed next door but the plant is yet to spread to your property, then your options for legal action against your neighbour are limited.

Talking to the person responsible for the land should be your first port of call before taking any further action. Open up a discussion with your neighbour, letting them know that knotweed is present on their property. In some cases, it may be that the neighbour is renting and the landlord is simply unaware that they have an infestation on their hands.

If your neighbour has allowed Japanese knotweed knotweed to spread into your garden, you should inform them of this. If they do not take reasonable steps to control the knotweed after they’ve been informed of the infestation, then you should be able to appeal for a Community Protection Notice from your local authority to force them to do so.

A number of recent court cases reveal just how costly leaving knotweed to its own devices can be. In early 2018 Adam and Eleanor Smith successfully sued their neighbour after they discovered a serious knotweed infestation on their land which had entered from an adjacent property.

They were able to claim for the costs of removing the knotweed and their neighbour had to commit to a 5-year treatment plan, to ensure that the infestation would not return. This result proves that turning a blind eye to your knotweed problem is not a good idea, especially when it is threatening to leave the confines of your land.

Who is responsible for clearing Japanese knotweed?

Deciding who is responsible for clearing the Japanese knotweed should be the first step to take after the positive identification of the plant. According to the Wildlife and Countryside Act 1981, it is the responsibility of the landowner to prevent the spread of Japanese knotweed into the wild, or neighbouring properties.

There is no legal stipulation to clear Japanese knotweed from one’s land however, if the plant is allowed to spread from your land onto a neighbouring property then you will be responsible for clearing that infestation. It must be proved that the knotweed originated on your land in order for you to be held responsible for clearing it, as in the case of Smith v Line. In this case, the defendant (Miss Line) was found to be preventing the claimants’ enjoyment of their land by not treating her knotweed infestation, she was ordered to treat the infestation on her own land and pay the claimants’ legal fees.

How to legally prevent the spread of Japanese knotweed

You are legally required to prevent Japanese knotweed on your land spreading into the wild, or onto neighbouring land. Japanese knotweed spreads via the transferral of contaminated soil, or the unlawful tipping of cuttings.

You will be liable for the spread of the plant even if you have attempted to stop its spread by composting or burying it. Japanese knotweed is a resilient plant that can often persist through adverse conditions, so it’s imperative that your treatments are thorough and effective.

The Property Care Association has put together a comprehensive document detailing the best practice for the three key methods of preventing the spread of the plant.

Can you spray Japanese knotweed with chemicals?

There are a few proven methods of managing Japanese knotweed. If you’re planning on digging up and removing your knotweed manually then you’ll need to adhere to the aforementioned waste legislations laid out in the Environment Protection Act 1990 and the Wildlife and Countryside Act 1984.

Using herbicide sprays to remove Japanese knotweed is not an instant fix, depending on the size of the infestation it may take up to 3 years for the treatment to soak down into the rhizomes underground. Before you begin treatment you should ensure that the person spraying holds a certificate of competence for herbicide use, or works under the supervision of someone who has one. You’ll also need to ensure that you keep in mind the Control of Pesticides Regulations 1986. These regulations require any person using pesticide to take all reasonable precautions in order to protect the health of their fellow human beings, other creatures and plants.

If your infestation happens to be close to a water source you’ll need to apply for approval from the Environment Agency. You may also need to get permission from Natural England, in cases where the land you’re treating is protected.

Can you bury Japanese knotweed?

You are only allowed to bury your Japanese knotweed waste on your land if you have permission from the Environment Agency; you should leave at least a week’s notice to inform them. Usually, you will be advised to take your waste to a landfill that has the requisite permit to deal with the plant.

In the event where you are granted permission to bury your Japanese knotweed waste on your own land then you must adhere to a handful of guidelines to ensure that the plant does not make a resurgence once more. Burying waste at a depth of at least 5 metres and then covering the remains with a root barrier membrane layer is advised. A depth of 2 metres is acceptable, but in this case you must wrap the remains completely in the membrane layer. In both cases, you should not bury any other types of waste with it.

Can you burn Japanese knotweed?

Burning Japanese knotweed is one method of removing an infestation, however you must ensure that you have effectively removed every part of the plant from your land beforehand, otherwise your infestation will return again.

Business owners should give the Environment Agency a week’s notice before burning knotweed and should also inform the environmental health officer at their local council. You’ll need an environmental permit or registered waste exemption before you start burning your Japanese knotweed waste.

If you’re a private landowner then you do not need to ask permission from the Environment Agency, but you might want to check with your local council that you’re allowed to go ahead with burning your knotweed. Japanese knotweed crown and rhizomes (which make up the roots of the plant) can survive burning. Any remains should still be treated as controlled waste and be disposed of accordingly.

Can you remove Japanese knotweed yourself?

Whilst removing Japanese knotweed yourself is legal, it is incredibly difficult to do so thoroughly. If you do not remove every last trace of knotweed, it can grow back and spread even further. This is why we recommend hiring a PCA accredited specialist to get your knotweed treated and your legal matters, if you have any, resolved quickly.

How to get rid of Japanese knotweed legally

Allowing Japanese knotweed or soil contaminated with the plant to spread into the wild is an offence and could result in a fine of up to £5000, or a prison sentence of up to 2 years. It’s important that you either supervise the disposal of the infestation yourself, or hire a specialist to take responsibility for it. Trustworthy firms that you can rely on will belong to trade bodies such as the Property Care Association (PCA) or the Invasive Non-Native Specialists Association.

Related: How to get rid of Japanese knotweed

How to use a waste carrier to take Japanese knotweed off-site

If you’re planning on moving knotweed, or knotweed contaminated soil, off-site then you must use a registered waste carrier and ensure that the waste is taken to a licensed landfill site. These registered carriers are still bound by the law in regards to disposing Japanese knotweed and must not dispose of waste along with surplus soil, or sell any contaminated soil.

Before you transfer any knotweed contaminated waste you must warn the waste site that you are about to transport an invasive plant and confirm that they have the correct permit to deal with the plant. Ensure that any waste is also covered or enclosed within the vehicles that you’re using for the task.

After you transfer Japanese knotweed waste

You should thoroughly inspect your vehicle after moving Japanese knotweed waste with it, this includes brushing down the body, jet-washing tyres and ensuring that there are no remains of the plant trapped within the vehicle.

Full list of resources related to Japanese knotweed legal advice:

If you’ve more questions about Japanese knotweed legislation or are seeking further legal advice in regards to a Knotweed infestation then please don’t hesitate in calling us on 07595 653 226 or sending us a message using the contact form.

Paolo Martini

Paolo Martini is the lead solicitor for Knotweed Help and has over 30 years of experience in the field of Civil Litigation and is an expert on the legal issues faced by individuals dealing with Japanese knotweed on their land. Now considered one of the country's leading litigators in Japanese knotweed law he works alongside the country’s top barristers and experts. His in-depth legal experience and connections to the Japanese knotweed removal industry make him uniquely suited for handling your case.