Understand the laws regarding Japanese Knotweed

According to some reports, homeowners are not aware of their legal responsibility to stop Japanese Knotweed spreading. Only 36% of them know they can be sued and only 18% are aware that they could face criminal prosecution. Japanese knotweed should not be ignored. This page contains information that will help you understand the laws regarding Japanese knotweed.

Japanese Knotweed can grow in the garden of a landowner’s property. He should take every precaution to prevent the invasive weed spreading to neighbouring properties. If this fails, he could be held liable for any damage that was caused by the encroachment. If the knotweed is growing on your property, the landowner could be held responsible.

Give Notice to Your Neighbour

If you want to sue your neighbour, you should give the person or organization responsible for the adjacent land the chance to address the nuisance (knotweed) unless it has been there for quite some time and must be obvious that they are already aware. You should notify your neighbours as soon as possible. Also, make sure you specify what actions you want the landowner to take.

You should ask your neighbour to treat knotweed on their property as well as on theirs. Ideally, the remedy they choose should also include a guarantee. You should also include a description of the possible consequences for them if they ignore the notice. If the knotweed is from commercial land or infrastructure like Council or Network Rail, they are more than likely already aware.

Unreasonable Conduct

A Community Protection Notice (CPN), which can be used under the Act, can be used to order someone to stop or control the growth of Japanese knotweed and other plants that could cause serious problems for communities. The conduct of an individual or body must have a negative effect on the quality or life of others in the area. Section 57 of the Act defines conduct as “a failure to act”. CPNs could be used to force someone to stop or control the growth of Japanese knotweed, or other plants that can cause serious harm to communities.

Fixed Penalty Notice

If an individual or organization isn’t controlling Japanese knotweed, or any other invasive plant, and it could reasonably be expected that they would, the CPN could then be used. A mandatory written warning must be served before the CPN can be used to force them to cease their anti-social behaviour. A community protection notice violation without reasonable excuse would be considered a crime and subject to a fixed penalty. A summary conviction would result in a fine of not more than PS2,500 for an individual. A fine of not more than PS20,000 is possible for an organisation such as a company.

Paramount Knotweed Management Plan

Knotweed is not a reason to deny a mortgage application. Instead, it should be considered on a case-by-case basis. A suitable Knotweed Management Plan must be presented. It can be shocking to discover that your property has knotweed or that your property is infested. However, there are ways to control the infestation. The Knotweed Management Plan is the key.

Legal Rights Against Misrepresentation

Japanese knotweed is a serious problem in the country. The seller must disclose this information to you when buying a house. If the Japanese knotweed is present in a property you’ve purchased, you may sue the seller.

Property value loss

Knotweed infestation can cause property value loss. If a property is found to be infested with Japanese knotweed or Japanese knotweed within 7 metres of the property, it will make it extremely difficult to obtain a mortgage.

A property that is affected by Japanese knotweed loses its value, regardless of whether it is within their boundaries or within 7 metres. This is known as diminution of value. It may be possible to include a claim of diminution in any settlement if you succeed in bringing a Nuisance Claim on a defendant.

Professional Negligence

If you paid for a professional inspection of your property, and the surveyor failed to notice the Japanese knotweed, then you could file a claim for professional negligence against the surveyor. You can file a claim if you can prove that the surveyor should’ve noticed the Japanese knotweed.

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Japanese Knotweed and its detrimental affect on the property industry

The property industry is being hit with problems caused by Japanese knotweed. In just 10 weeks, it can grow 10 cm per day and can reach a height of 3-4 meters. It is illegal for someone to cause or allow the invasive plant spread onto another property.

A new study has shown that the UK has seen an astonishing 28% increase in Japanese knotweed cases in the last five years.

The results of analysing 29,536 confirmed cases of Japanese knotweed in the UK from 49 environmental organizations including National England, Environment Agency and National Trust were reached. The Japanese Knotweed Agency has also started a National Register for England and Wales.

It is extremely difficult to remove the underground roots of this plant. The nationwide treatment of the invasive plant may take up to three decades.

Ask your surveyor to check for Japanese knotweed or other invasive plants when you hire them as a consultant for your new home purchase.

This is particularly important if your property borders an existing or old railway line or is near a river, canal, or stream, Council land or commercial property.

Horticulture conducted a YouGov survey previously to learn more about the plant’s impact on the property market.

According to the YouGov survey, 4/5 of UK homeowners said they wouldn’t buy a house with Japanese knotweed. Just under half of those who said they would still buy the house agreed to lower the price at least 10%.

Many homeowners are not familiar with the plant, according to the survey. The reason is that only half of respondents could identify Japanese knotweed using a selection of photographs.

Questions remain about the government’s response to Japanese knotweed.

A national eradication program was proposed in 2015, but it was rejected by the government due to the staggering £1.5 billion cost.

Due to the current year’s weather, Japanese Knotweed is fast-growing and an invasive plant. This causes homeowners more problems than ever.

Its wet and frosty spring was followed by sunshine and dry weather earlier in the year. Experts are anticipating a rise in Japanese Knotweed incidence, which is already flourishing and growing rapidly.

Buyers and sellers must realise that there is a real possibility of an infestation or evidence of it in their property. This could cause a property to be unable to sell or stop selling.

Japanese Knotweed is a legal requirement for home sellers. The TA6 Property Information Form is used to notify buyers about any negative aspects affecting their home. It also includes a question pertaining Japanese Knotweed.

It is difficult to get a mortgage for a property that has Japanese Knotweed or had it in the past. Many home insurance policies won’t cover Japanese Knotweed. They also won’t cover damage to neighbouring properties or the cost of removing or eliminating the plant.

Japanese Knotweed is classified as a controlled waste under the Environmental Protection Act 1990. It can grow up to 20cm per day. If it is not controlled, its roots can reach deep into foundations and cause damage to walls and drainage systems.

It must be removed and disposed of by an expert. The cost will vary depending on how large the infestation is.

For homeowners, the only way to protect against any damage or remediation caused by Japanese Knotweed in their home is to purchase a Japanese Knotweed-specific insurance policy.

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How Did Japanese Knotweed Get Here?

Japanese Knotweed is a contentious plant that can depreciate the value of a property and cause conflict between neighbour’s. The invasive plant is known for spreading quickly and for monopolising gardens. Knotweed grows in large patches that can quickly push out any other competing plant life. Thankfully, Japanese Knotweed is easy to identify, so homeowners can waste no time in getting a treatment plan in place to get rid of the plant.

Although there is plenty of discussion regarding how Japanese Knotweed spreads, and what to do if you’ve bought a property with Knotweed, how this plant first got to the UK is not usually discussed. Japanese Knotweed’s history is an interesting one and can help give insight into why it has flourished so well in the UK and what lessons can be learned when dealing with invasive plants in the future.

Where is Japanese Knotweed originally from?

Japanese Knotweed is originally from Japan and is also native to China and Korea. The plant is one of many species of plants that have been discovered to be growing on the side of volcanoes. In its native land, Japanese Knotweed can reproduce naturally and also benefits from a prodigious underground system of rhizomes. In its native environment, Knotweed is kept in check by natural predators in the form of fungi and insects, not to mention other plants and an environment that can be much more hostile than the United Kingdom.

The plant was originally discovered by Dutch naturalist Maarten Houttuyn in the 18th-Century, he named it Reynoutria japonica, a name which it still goes by today. Unfortunately, the records of this original discovery were lost for some time, so when more European botanists started exploring Japan some 150 years later, the plant was rediscovered and given a new name by a Bavarian botanist, Phillip von Siebold. Siebold and his partner Zuccarini, named the plant Polygonum cuspidatum. It wasn’t until the turn of the 20th century that a Japanese botanist by the name of Makino, discovered that Houttuyn and Siebold’s plant were one and the same.

Who brought Japanese Knotweed to the UK?

Philip von Siebold brought Japanese Knotweed to the UK in 1850, unaware of the impact that it would go on to have on the environment. At the time, botany and the cultivation of plants was a popular interest of the upper classes. Botanist like Siebold would be able to fund their research trips by sending their discoveries back to nurseries on the European continent, where they would then be cultivated and sold onto commercial nurseries or botanical gardens around the world.

Why was Japanese Knotweed imported to the UK?

Japanese Knotweed was imported to the UK for commercial sale and botanical cultivation. Over the time that he spent in Japan, Siebold collected and recorded over 1,000 different plants, often choosing to plant them in the garden behind his research base on Dejima, an artificial island near Nagasaki. Periodically, Siebold would box up a number of samples and send them back to his home in the Netherland. From their new home in Leiden, these plants would be carefully grown and the packaged up for botanical gardens in Belgium and Britain, with an unmarked box containing Japanese Knotweed arriving at London’s Kew Gardens in 1850.

Kew Gardens often relied on these boxes of new plants to keep their own collections diverse and interesting for visitors. After discovering how quickly the plant could grow in Britain, the horticulturists there recognised Japanese Knotweed as a plant that could be easily cultivated and sold on to budding gardeners. Soon the plant was being distributed to garden nurseries around the country and then shared in cuttings by enthusiastic gardeners. In addition to being intentionally spread by people, the plant also began to spread by its own means, populating river banks and finding new routes to the rest of the country along roads and newly built railway lines.

Where does Japanese Knotweed grow in UK?

Japanese Knotweed now grows in almost every area of the UK. The plant was given free rein to spread throughout the country for over a hundred years before being recognised as invasive by the government. By the time Japanese Knotweed was identified as an invasive threat in 1981, it had already been spread by gardeners, dug up and transported by urban development projects and even used to stabilise soil on the sides of railway lines.

The plant is frequently found growing alongside public watercourses such as canals, as well as near railway lines, motorways and public footpaths. Japanese Knotweed thrives in most conditions in the UK and is often found growing on land that has been abandoned or left unattended. For this reason, large infestations can often be discovered in overgrown back gardens, or on abandoned industrial sites.

How common is Japanese Knotweed in the UK?

Japanese Knotweed is a very common sight in the UK. Since the government has made the spread of Japanese Knotweed a more pressing concern, efforts have been made to track where it has been growing throughout the country. Using these statistics, it’s been possible to recognise the areas of the country that have been most affected by Japanese Knotweed. Bolton, Bristol, Conway, Rotherham and Nottingham are areas in the UK that have been affected the most, however exact numbers are difficult to assess

What do I do if I find Japanese Knotweed?

If you find Japanese Knotweed it’s important to ascertain where the plant has come from and to what extent the plant affects your property. You may want to consider contacting a Japanese Knotweed specialist to make a positive identification before you move forward with talking to any neighbour’s who might also have the plant on their land. Ignoring the infestation is not advised, as the plant can quickly multiply, leading to a larger problem to deal with and potentially more costs, if you find that it’s not possible to claim compensation for the cost of treatment.


If you think you’ve found Japanese Knotweed and would like some advice on what to do next, then you can contact us by calling freephone 03335 777 888 or send us a message using the contact form on this page.

Polygonum bidwelliae

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How Japanese Knotweed Affects House Insurance: Are You Covered?

Japanese Knotweed can have a negative impact on the value of your property, not to mention causing conflict between neighbour’s and causing stress in your day-to-day life. Discovering a Japanese Knotweed infestation can also lead to some very expensive costs, which many might wish to alleviate by relying on their home insurance. Unfortunately, making a claim on your home insurance after discovering Japanese Knotweed is not always straightforward, or even possible, in some cases.

Does house insurance cover Japanese Knotweed?

Most house insurance policies will not cover losses incurred as a result of Japanese Knotweed. However, there are some exceptions to this rule, such as if the plant has caused subsidence, or if it has spread from a neighbouring property. Having Japanese Knotweed on your land also might prompt other questions, such as how it could affect your premiums and if your insurance might cover the legal costs of a Japanese Knotweed claim made against you.

Will my insurance provider pay for treatment of Japanese Knotweed?

Home insurance providers will not pay for treatment of Japanese Knotweed. If you have discovered the plant on your land and can prove that it has either entered from a neighbouring property, or the seller has lied about the Japanese Knotweed, then you may be able to claim compensation to cover the cost of damages.

Am I covered for damage caused by Japanese Knotweed?

Standard house insurance policies do not typically cover the costs related to repairing the damages caused by Japanese Knotweed growing on your land. However, in the case that the Japanese Knotweed has caused structural damage to your home, like subsidence, you may be able to claim for damages. Although, successful claims are only likely to be made when you can prove that you have taken reasonable steps to eradicate the Japanese Knotweed before the subsidence took place.

This is a good example of how important it is to not delay dealing with a Japanese Knotweed infestation, doing so can result in serious repercussions such as the above, as well as the potential legal implications of allowing the plant to spread to a neighbouring property.

Will my insurance cover Japanese Knotweed from a neighbouring property?

Depending on your policy, your insurance may cover the cost of repairing damage caused by Japanese Knotweed entering from a neighbouring property. In this circumstance, your insurers may seek to pursue your neighbour’s for the costs related to the damage to the property.

Will my insurance cover legal expenses if my neighbour claims for Japanese Knotweed damages?

Your insurance policy might cover the cost of legal expenses in the event that your neighbour attempts to claim for compensation for damages caused by Japanese Knotweed entering your land.

It is against the law to allow Japanese Knotweed to spread from your land into a neighbouring property, regardless of if it’s publicly or privately owned. If your neighbour can prove that you have allowed the plant to spread into their land then you could be found liable for the loss of value of the property, as well as any treatment costs that the infestation might have incurred.

In most cases, you are able to add-on legal expenses insurance on to your standard home insurance policy. You may wish to assess the fine print in your current policy if you’re worried that you might not be covered for this eventuality.

Do I need to inform my insurance provider that I have Japanese Knotweed?

You do not need to inform your insurance provider about the Japanese Knotweed on your land. In the event that you find Japanese Knotweed on your property, you should do as much as you can to prevent it further spreading and causing damage to your property. If you fail to do this, your insurance provider may decline a future claim for damage caused by subsidence, on the grounds that you have acted negligently in not treating the problem sooner. In the eventuality that you are directly asked about the presence of Japanese Knotweed on your property by your insurance provider, you must be honest with them.

Can I get house insurance if I have Japanese Knotweed?

You can still get house insurance if you have Japanese Knotweed on your land. As standard house insurance policies do not tend to cover the costs of removing Japanese Knotweed or the damages caused by the plant to the property insurers are not likely to take this into account. However, in the case that you are directly asked about having Japanese Knotweed, it’s recommended to answer honestly and openly.

Will having Japanese Knotweed affect my house insurance premiums?

Having Japanese Knotweed shouldn’t affect your home insurance premium. Most standard house insurance policies will not cover the removal of Japanese Knotweed, or repairs to anything damaged by it. As such, your discovery of the plant, whether or not it has originated on your land, should not affect your premiums.

However, in the case that you plan on claiming for damages related to subsidence caused by Japanese Knotweed, you will likely find that your premium will increase. Don’t forget that, in the event that you do make a successful claim, you will also have to pay the excess laid out in your policy. Claiming for subsidence cover can also negatively impact your ability to get insurance cover for subsidence in the future, as your home will have been flagged as high-risk by the insurance companies.

What insurance do I need to cover me against Japanese Knotweed?

Since 2015, it has been possible to buy specific Japanese Knotweed insurance which covers the cost of removing the plant, and the potential costs related to claims against you, as a result of the Knotweed spreading to a neighbouring property.

A Japanese Knotweed indemnity insurance policy will cover the costs of treating and removing the infestation, in addition to preventative insurance-backed measures to stop the plant from returning. The policy should also cover the cost of a Japanese Knotweed survey, as well as any reparation costs in relation to damages to the property and legal expenses paid for as a result of claims made against you. These policies were created with the intention of easing the conveyancing process, in cases where homes have been affected by the plant.

Japanese Knotweed insurance policies are usually for 10 years, with the limit of indemnity being based on your property’s market value, offering valuable protection to both you and your mortgage lender. It should be noted that these Japanese Knotweed indemnity policies are only available for residential properties where the presence of the plant is not known, or if treatment has taken place to the satisfaction of the mortgage lender.

Too little, too late?

Unfortunately, Japanese Knotweed indemnity policies, such as the above, have not been advertised to their full extent, so for many, the discovery of them will be a case of too little, too late. If you’ve found Japanese Knotweed on your land, and have found that your insurance does not cover the costs of repairing damages or removal, then you may be able to seek compensation against the seller of the property or even the persons or organisations who have allowed the plant to spread to your land.


Get in touch with us by sending a message using the contact form, or calling us freephone 03335 777 888

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Has Your Surveyor Missed Japanese Knotweed?

espite Japanese Knotweed having made a significant impact on the property industry in the last decade, there are still cases where surveyors miss this invasive plant whilst conducting mortgage evaluations, Home Buyer Reports and RICS Building Surveys. In many of these scenarios, buyers are left in a precarious place, having already invested hundreds of pounds into the home buying process and often reaching the point of no return before making the discovery of an infestation.

The following guidance is intended for those who have discovered that their surveyor has missed Japanese Knotweed:

Do surveyors look for Japanese Knotweed?

RICS qualified surveyors are trained to look for large masses of vegetation that could signify an invasive plant infestation. A professional surveyor is expected to keep up to date with ongoing development in their industry, which includes the common risk factors that could point to a Japanese Knotweed problem. The RICS have laid out an assessment framework in their resource materials for Japanese Knotweed which includes pre-inspection checks of the local area, an inspection of the property itself and even inspection of neighbouring communal areas.

The RICS notes pertaining to Japanese Knotweed lay out four distinct categories that property surveyors can use to inform their process. It’s important to note that each of these categories refers to the Japanese Knotweed being within 7 metres of either habitable spaces, buildings or boundaries. This ‘7-metre rule’ is based on the assumption that Japanese Knotweed has the capacity to grow up to 7 metres underground from the point that it can be spotted on the surface. This rule has come under scrutiny by the government who have suggested that it has been misused within the property industry, however, it has yet to be replaced by the RICS.

The four categories are ordered here in descending order from most severe to the least:

4: “Japanese Knotweed is within 7 metres of a habitable space, conservatory and/or garage, either within the boundaries of this property or in a neighbouring property or space; and/or Japanese Knotweed is causing serious damage to outbuildings, associated structures, drains, paths, boundary walls and fences and so on. Further investigations by an appropriately qualified and/or experienced person are required.”

3: “Although Japanese Knotweed is present within the boundaries of the property, it is more than 7 metres from a habitable space, conservatory, and/or garage. If there is damage to outbuildings, associated structures, paths and boundary walls and fences, it is minor. Further investigations by an appropriately qualified and/or experienced person are required.”

2: “Japanese Knotweed was not seen within the boundaries of this property, but it was seen on a neighbouring property or land. Here, it was within 7 metres of the boundary, but more than 7 metres away from habitable spaces, conservatory and/or garage of the subject property.”

1: “Japanese Knotweed was not seen on this property, but it can be seen on a neighbouring property or land where it was more than 7 metres.”

In the case where the surveyor deems the infestation to be of a category 3 or 4, then further investigations should be undertaken by an ‘appropriately qualified and/or experienced person’ in order to create a ‘management plan’. In the case where the infestation is classed as a category 1 or 2, the surveyor will decide if further investigations are warranted, depending on their client’s requirements and on their own professional judgment.

Should an RICS survey pick up the presence of Japanese Knotweed?

Whether or not a particular survey will identify Japanese Knotweed will depend on the type of survey that has been commissioned, the scale of the potential infestation, the professionalism of the surveyor and also the extent to which the owner of the property has attempted to conceal the plant.

Not all surveys are created equal. The RICS has a few different types of surveys which cover a range of budgets and scenarios. The cheapest of these is the RICS Condition Report, which costs around £250 and is intended to provide basic information regarding potential legal issues and any urgent problems that the property faces. In the RICS’ words, the visual inspection of the grounds is a ‘relatively cursory’ part of the process, however in cases where the surveyor is aware that there is a greater risk of Japanese Knotweed then this may require ‘particular attention’ on the part of the surveyor. Whilst the RICS materials do say that a client should purchase a Home Buyer Report or building survey if they wish to have ‘greater assurance’, this does not excuse a surveyor from completely missing Japanese Knotweed in their survey.

Should a mortgage valuation pick up Japanese Knotweed?

A mortgage valuation is not always guaranteed to pick up the presence of Japanese Knotweed. A mortgage valuation survey is paid for by a mortgage lender or bank in order to verify that the amount of money that they’re planning on lending is in accordance with the value of the property in question. A valuation is intended to satisfy the mortgage lender, as such, it will not single out any structural issues, or repairs that will need addressing before a purchase is made. Although the prospective buyer is usually expected to pay for the valuation, a surveyor might not focus their attention on the land surrounding the property.

How can a surveyor miss Japanese Knotweed?

Surveyors can miss Japanese Knotweed on a property for a number of reasons, not all of which suggest that they have acted negligently. Homeowners can often act fraudulently when attempting to sell a property infested with Japanese Knotweed, relying on cheap tricks to hide their infestation in order to push the sale through expediently. A property owner could choose to conceal the Japanese Knotweed by burying shoots in the spring with wood chips or topsoil. They might also choose to hack away any evidence of the plant above the surface and fly-tip the evidence.

DIY attempts at treating Japanese Knotweed can lead to deformed or sparse growth which may lead surveyors to miss the infestation altogether, or mistakenly identify it as another plant. Similarly, if the homeowner has paid for a professional removal service then the Japanese Knotweed might have entered into a dormant phase, where it might remain below the surface for years – completely undetectable to anyone.

In cases where property developers have built on land with Japanese Knotweed, the infestation might have been dispersed into the earth that your home has been built on. As Knotweed rhizomes can grow from a thumb-size piece into a full-size plant given enough time, a surveyor could easily miss the plant if it is still growing underneath the ground.

What happens if a surveyor missed Japanese Knotweed growing on a property you wish to buy?

If a surveyor missed the presence of Japanese Knotweed on a house before a purchase is made then the prospective buyer will be unable to rely on legal action to claim back any expenses that might have been accrued leading up to the discovery. Although the potential buyer might have already invested money in seeking a valuation and surveying the property, not to mention spending resources setting up the sale of their own home, unless a contract has been signed, they won’t be able to claim these expenses back from the negligent property surveyor.

What if you buy a house and then discover that the surveyor missed Japanese Knotweed on the land?

The discovery of Japanese Knotweed on a property can lead to the home being devalued by as much as 5% and can sometimes result in a mortgage lender or bank refusing to lend. A surveyor missing Japanese Knotweed can lead to sales falling through and thousands of pounds being wasted. If a Japanese Knotweed infestation is discovered on a property after a Home Evaluation Report or RICS Home Buyer Survey has said otherwise then the buyer may be able to bring legal action against the surveyor for professional negligence.

Can I sue my surveyor for missing Japanese Knotweed?

It is possible to sue a surveyor for missing Japanese Knotweed, in the event that the sale has of the house has gone through and it can be proved that the surveyor has acted negligently. Courts or tribunals will refer to the resources supplied by the RICS in order to determine whether or not a surveyor has acted negligently in missing Japanese Knotweed. In assessing each case attention will be paid to the lengths that the surveyor went to survey the property, the context surrounding the property, whether or not there’s Japanese Knotweed in neighbouring properties and any notes or recommendations that the surveyor might have made at the time of the survey.

Do surveyors have a duty of care to potential buyers?

According to the RICS Rules of Conduct, all members are required to carry out their work with ‘due skill, care and diligence and with proper regard for the technical standards expected of them’. , In addition to upholding the professional standards expected of them, all surveyors are required to maintain their professional competence by staying up to date with developments in their industry. Surveyors have a duty of care to both the lender and the homebuyer, regardless of if the owner has attempted to hide the infestation. Whether or not a surveyor is deemed to have properly performed their duty of care will depend on the context of the given case, including the type of survey that was ordered and the nature of the property.

Is there precedence for buyers suing surveyors for missing Japanese Knotweed?

In May 2019, Paul Ryb was awarded £50,000 after his RICS Level 3 Building Survey failed to pick up the Japanese Knotweed that was growing in the garden of his ground-floor London flat. Being partially sighted, Mr Ryb was relying completely on the professional opinion of the property surveyor who completely missed the plant on his survey of the building. The £50,000 awarded to Mr Ryb reflected the reduction in value of his £1.2 million home, in addition to the thousands of pounds that he was forced to spend on excavating the infestation. Mr Ryb was also awarded £90,000 to cover the costs of his legal fees.


Call us today on freephone 03335 777 888 or send us an enquiry using the contact form to see if we can help you with your Japanese Knotweed problem.

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Your Japanese Knotweed Legal Obligations

Japanese knotweed has been in the UK for more than a century, having been introduced by the Victorians in the 1800s. Native to China, Taiwan and Japan it was first brought to the UK as an ornamental plant for the garden. Fast forward in time and the plant is renowned now for being an invasive weed species. The growth of this plant is rigorous and it can spread as much as 2 metres in one growing season.

Because it’s growth is so aggressive and invasive, a number of Japanese knotweed laws were introduced in order to control its growth, and restrict its transportation. Homeowners need to be aware of Japanese knotweed legal responsibility and ensure they meet their Japanese knotweed legal obligation. It can quickly take over your garden and native species, as well as potentially reduce the price of your house.

What is the Law on Japanese Knotweed?

In the UK, the Japanese knotweed legal obligation is that it’s illegal to plant it or allow it to grow in the wild. It’s not, however, an offence to let it grow in your garden or on any land that you own. Your Japanese knotweed legal obligation also prohibits you from allowing it to escape and spread into a neighbour’s garden. It pays to be aware of your legal responsibilities if you want to avoid a costly day in court or problems with your local council or neighbours.

There are a number of laws that relate to the controlling of Japanese knotweed. They include:

Japanese Knotweed Anti-Social Behaviour Law

The negligent cultivation of Japanese knotweed came under the remit of the Anti-social Behaviour Crime and Policing Act 2014. Authorities, such as the local council and the police are able to issue Community Protection Notices if you are found to be negligently cultivating this invasive plant. The notice requires you to remove the species from your property and/or prevent its return. Failure to comply could result in a substantial fine.

EPA (Environmental Protection Act) 1990

This is the main legislation that relates to Japanese knotweed. The law gives details of methods to remove, transport, and dispose of the plant, considered to be “controlled waste”. As well as covering the plant itself, the legislation also covered plant materials or soil that could potentially be contaminated. Disposing of contaminated soil or plant material in an irresponsible way could result in a large fine.

Wildlife and Countryside Act 1981

This legislation supports the EPA of 1990 and relates to the growth of Japanese knotweed in the wild. Anyone found growing it in the wild faces a £5,000 fine, or a stay of 6 months in prison. You might think this is a little heavy but it does show how serious allowing the plant to grow unchecked is considered.

How to Recognise Japanese Knotweed

It’s quite easy to confuse Japanese knotweed with other common plants, but there are some very clear signs to look out for. During the summer, the green leaves are broad and shaped like a shield. The stems are reddish and hollow, much like bamboo. In the winter, the plant dies back, leaving stems that become brown and brittle.

What Can You Do if There is Japanese Knotweed in Neighbours Garden?

Your neighbour is under no Japanese knotweed legal obligation to remove it if they have it in their garden. If it starts to spread into your property, however, it is considered a private nuisance and you are legally permitted to take them to court. The best course of action is to talk to them about the problem and suggest they seek the help of a professional Japanese knotweed specialist. They might not be aware there is a problem, and by letting them know it is spreading to your garden, it gives them the opportunity to resolve the problem before it gets too costly.

There are plans to introduce predators and knotweed disease from Japan, but currently, the best course of action, if you’ve got it in your garden and want it removed, is to enlist the help of a professional Japanese knotweed specialist.

To find out more about our services, give us a call today on freephone 03335 777 888

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Has Your Property Seller Lied About Japanese Knotweed? Here’s What To Do

Research reported by The Independent has suggested that the discovery of Japanese Knotweed can have a major impact on the house buying process. It’s estimated that 75% of buyers are put off when they discover that Japanese Knotweed is present. Considering the damaging effect that it can have on house prices, it’s hardly surprising that some unethical sellers might choose to lie about the presence of Japanese Knotweed on their property. Those that do so risk serious legal complications which may cost them more than a quick sale ever could make them.

What happens if a seller lies about Japanese Knotweed before the sale?

Selling a house with Japanese Knotweed can be challenging. The plant is now well-documented, as well as its damaging impact on home values. Informed buyers are now much more vigilant when inspecting properties, this has led to some sellers choosing to lie about the presence of Japanese Knotweed in order to push through a quick sale and thereby rid themselves of the property. These scenarios lead to a great deal of wasted time and money on behalf of the prospective buyers. A prospective buyer may have arranged the sale of their existing home, paid for surveys and legal fees before discovering the Japanese Knotweed and being forced to pull out of the purchase. As no contract has been signed between the two parties at this point, the seller cannot be made liable for the costs that the buyer has incurred in the lead up to the failed house purchase.

What can I do if I discover the seller has lied after the sale has been finalised?

If the Japanese Knotweed infestation is discovered after the sale has been put through then the buyer is in a better position to claim for damages, as a formal contract has been signed. Those who have bought a property with Knotweed may be able to claim compensation against the owner for misrepresenting the property, depending on the level of deception or negligence on the part of the seller.

Can I sue the seller for misrepresentation if they lie about Japanese Knotweed?

If a seller lies about Japanese Knotweed in the lead up to the sale then they may find that they have to compensate the new owner for misrepresenting the property. It’s possible to pursue a no win no fee property misrepresentation claims against a previous seller in the case that the buyer has been misled to believe that there is no Japanese Knotweed present on the property, or even if the seller has failed to mention the presence of Japanese Knotweed.

Can estate agents lie about the presence of Japanese Knotweed?

Estate agents have an obligation to present properties as honestly as possible. They’re bound by Consumer Regulations that have been put in place to ensure that agents aren’t allowed to simply lie about the homes that they’re selling. These regulations also require estate agents to inform any potential buyers about any materials facts that would affect the decision to make the purchase. Guidelines appended to these regulations stipulate Japanese Knotweed as ‘material’, so an ethical, professional estate agent should not lie about its presence. If they are proved to do so then they are open to claims from the buyer dealing with them and they could be banned from working as an estate agent.

What if a seller knows about the Knotweed but is not specifically asked about it by the buyer?

One of the tenets that is often discussed when dealing with enquiries related to purchasing houses is ‘buyer beware’. The basic premise of this being that if a buyer does not ask the seller specifically about certain aspects of the house, then the buyer will not be able to claim compensation when they discover something untoward about the property. The introduction of the TA6 Property Information Form has helped to avoid situations where sellers avoid informing buyers about the presence of Japanese Knotweed, however, there are still some cases where they are not used, for example in certain property auctions.

What can I do if the seller lied on the TA6 property information form?

You’ll find the Japanese Knotweed related question at 7.8 on the TA6 form. It reads: Is the property affected by Japanese Knotweed?

There are three options that sellers can choose: Yes, No and Not Known.

Changes were made in February 2020 to the guidance notes on this question, adding context regarding the plant, the ‘Not Known’ option and also a secondary section for sellers to provide information about whether or not a Japanese Knotweed treatment or management plan is in place.

The guidance makes allowances for the fact that Japanese Knotweed can be hard difficult to spot for the uninitiated, however, it stresses that ‘No’ should only be selected when the seller is ‘certain that no rhizome (root) is present in the ground of the property, or within 3 metres of the property boundary even if there are no visible signs above ground’. By selecting ‘Not Known’, the onus is put on the buyer to commission a Japanese Knotweed survey to determine whether or not it affects the property.

This adjustment to the guidance also means that sellers who expressly lie about the presence of Japanese Knotweed put themselves at a much greater risk of being sued as a result.

What happens if the information provided in the TA6 form was correct when given to the buyer, but then incorrect by the time of purchase?

The seller of a property is obligated to ensure that any information they have provided to the buyer is kept up to date, right up to the day of the exchange. This means that if the seller initially reports, truthfully, that there is no Knotweed present on the property and then later discovers an infestation, they are obligated by law to inform the prospective seller. There is a stipulation in the standard TA6 Property Information Form that requires the seller to inform their solicitor in the event of a change in the answer that they have initially provided.  Failure to communicate this change could lead to potential claim against the seller for misrepresentation.


If you’ve found yourself in a difficult legal situation as a result of being lied to about the presence of Japanese Knotweed then our experts may be able to help you. We can find an accredited firm to treat your Japanese Knotweed and recommend a Japanese Knotweed regulated law firm to pursue legal action to compensate you for any costs incurred and diminution in your property value. Send us a message using the contact form or give us a call on freephone 03335 777 888

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Guide to Selling A Property with Japanese Knotweed

Since being introduced to Britain in the early 19th century, Japanese Knotweed has spread far and wide across the country, with very few corners of the land remaining unaffected. It has been labelled as an invasive plant by the government, and due to its incredible hardy qualities, has become a bane for homeowners who are looking to sell their properties. Japanese Knotweed remains in the Top 100 most invasive plant species in the world!

Japanese Knotweed can grow up to 10cm a day during the summer, can regrow from a fragment the size of a thumbnail and spreads via an underground network of rhizomes which can remain dormant beneath the ground for years at a time. This invasive plant used to be kept at arms’ length by mortgage lenders, with some flat-out refusing to lend on properties affected, however in recent years this stance has softened somewhat.

Selling a house with Japanese Knotweed is by no means easy, but can be done as long as the correct course is taken and the seller remains proactive and honest with all parties involved.

Where is Japanese Knotweed found?

Japanese Knotweed is often found on land that has been left unattended for a long period of time. A property may be at risk of having the plant if it is near land that is close to a public watercourse (such as a canal), or if it’s close to footpaths, schools and colleges, railways, motorways, car parks, cleared sites or commercial buildings. If your home is close to land that has been unattended to for a long time, then there’s a risk that Japanese Knotweed might be hidden within.

The commonly affected areas of a property, as laid out by the RICS in their guidance notes for surveyors are outdoor spaces and gardens. Japanese Knotweed is known to exploit structural weaknesses, which is why the guidance also lists drains, or buried services (such as gas pipes) as being at risk. Patios and driveways can sometimes hide the presence of the plant. Whereas boundary walls or small garden walls with shallow foundations can also often hide the plant until they are pushed over by the mass of the vegetation. Garden sheds, greenhouses and conservatories can also be at risk of damage.

How do I know if my house has Japanese Knotweed?

You can confirm that your house has Japanese Knotweed by finding the plant (in any of its forms) on your property. Making a positive identification will allow you to understand to what extent the plant affects the property, which should give you an idea as to how much the Japanese Knotweed will devalue your home. Identifying Japanese Knotweed can be as simple as finding a patch of brown canes, or spotting a handful of red shoots coming through the ground in spring. However, there are some cases where making a positive identification can be difficult. For example, in cases where land has been left to overgrow it can be hard to distinguish Japanese Knotweed from other plants, there are also many cases where the plant can be mistaken for others.

If you’re not confident in making an identification yourself then you may want to get a second opinion from a professional. Japanese Knotweed professionals could be removal firms, who have experience in identifying or treating the plant, or they could be RICS approved surveyors who have been trained to spot and calculate the extent to which the plant has affected your property. Getting an outside opinion should confirm whether or not you have Japanese Knotweed on your land.

How much does a Japanese Knotweed survey cost?

A Japanese Knotweed survey from a RICS surveyor on a standard residential property can cost from £200 up to £500, depending on the company that is undertaking the work. In some cases, you may find that a company will offer a free informal survey that will help you make a positive or negative identification of the plant on your property.

Japanese Knotweed Agency has an agreement with a law firm that will undertake the survey at their cost to progress a claim.

Can you sell a property with Japanese Knotweed?

You can sell a property with Japanese Knotweed; however, you may need to take some extra measures to ensure that potential buyers feel comfortable purchasing the house and confident that they will be able to secure a mortgage from their bank. This could involve either completely removing the plant from the property, or paying upfront for an insurance-backed treatment plan.

Despite banks having moved beyond their black and white intolerance of homes affected by Japanese Knotweed, it’s still the case that there is a stigma with these properties. In order to sell a home with Japanese Knotweed it’s important to prove that steps have been taken to control and if possible, remove the plant entirely from the property. As the removal process can take a number of growing seasons to eradicate, management plans cover 10 years and are usually insurance backed, so that treatment is guaranteed, even in the case where the original treatment firm closes.

How much does Japanese Knotweed devalue property?

Japanese Knotweed can devalue a property between 5 and 100%. There have been cases where homes have been completely devalued as a result of severe infestations, however, these are rare occurrences currently. The extent to which a property is devalued will depend on the severity of the infestation and the proximity of the Knotweed to the home. This devaluation will usually be equivalent to the cost of removing the plant and restoring the property to its original value.

Should I tell my estate agent about the Japanese Knotweed?

You should tell your estate agent about the Japanese Knotweed on your property, as in order to sell your home they need to be able to give potential sellers an honest impression of the house that reflects its true value. Choosing to hide or omit the presence of Japanese Knotweed could lead to a sale falling through at a later date, which could have a knock-on effect on your house purchase. If it is not declared and subsequently found out after purchase and aged giving a buyer the thought it was known and not declared, you could be the subject of a legal claim. Japanese Knotweed is no longer a rogue element, estate agents, potential buyers and surveyors alike are all aware of this plant, and attempting to hide it will likely end in the collapse of the sale or even a claim made against you.

Do estate agents have to declare Japanese Knotweed?

Estate agents must declare Japanese Knotweed in order to act within the Consumer Protection Regulations. If an estate agent chooses to lie or misrepresent a property as being free of Japanese Knotweed, then they could be reported to the National Association of Estate Agents. If they are found to have acted outside of the Consumer Protection Regulations then they could be banned from the profession. Do not trust an estate agent who promises to lie or omit the presence of Japanese Knotweed, as this person will be acting outside of the law if they do so.

Do you have to tell the buyer about the Japanese Knotweed?

You will need to tell the buyer about the Japanese Knotweed on your property in order to ensure that you are not misrepresenting the land. In most property conveyances, the buyer’s solicitor will request a TA6 property form from the seller.

The TA6 property information form is comprised of 14 sections, covering the property’s condition, any disputes the property may be connected to and whether or not the property has been affected by Japanese Knotweed. The question regarding Japanese Knotweed is:

“Is the property affected by Japanese Knotweed?”

There are three options to choose from: Yes, No or Not Known. It has been stressed in the guidance for these notes that you should only check ‘No’ when you are absolutely sure that there has not been any Japanese Knotweed present on the property. If it can be proven that you have lied on this form then you could be sued for misrepresenting the property.

Checking ‘Not Known’ puts the onus on the buyer to then commission a Japanese Knotweed survey, but if you are aware of the plant already, then choosing this option will waste the time of the buyer and likely put you in a weaker bargaining position when it comes to settling the eventual price of the home.

Do surveyors check for Japanese Knotweed?

Property surveyors do check for Japanese Knotweed; however, they might not always make this a priority when conducting a survey. Guidance laid out in the Royal Institute for Chartered Surveyors shows that surveyors are trained to pay particular attention to the possibility of Japanese Knotweed being present in cases where homes are at particular risk of having the invasive plant.

Although property surveyors are trained to check for Japanese Knotweed, there have been cases where surveyors have overlooked or altogether missed Japanese Knotweed. This has led to buyers going through with a purchase, only to discover later that they have paid an unfair price for a property that needs thousands of pounds of investment to cover the cost of removal.

What should you do if you’ve found Japanese Knotweed and want to sell your property?

If you want to sell your property, but have just discovered Japanese Knotweed, then your first step should be to speak to your neighbour’s. Whether you’re living in a terraced home or on several acres of land, if you have discovered Japanese Knotweed then it’s likely that the plant may also be on neighbouring land. In order to get a treatment plan in place that will satisfy potential buyers and their mortgage lenders, you will need to find out if the plant affects your neighbour’s land as well. Due to the quick spreading growth of this plant, it would be a pointless effort paying for removal only to find that there is an infestation that is months away from spreading back into the property.

Once you have a complete understanding of how far the plant has spread, you can enlist a Japanese Knotweed specialist to draw up a management plan that sets out how the infestation will be treated.

How much does Japanese Knotweed removal cost?

Japanese Knotweed removal costs can vary greatly depending on the severity of the infestation and the area of land that the plant covers. Removal firms tend to charge based on the square metres that have been infested by the plant, but not all charge the same rate. Regardless of the price paid, Japanese Knotweed removals should always come complete with a 10-year insurance backed guarantee and indemnity policy that ensures that the treatment will be completed.

As a guide, a typical semi-detached property with an infestation in the rear garden in several places could cost between £3000 and £5000 for a full treatment and monitoring plan and an insurance backed guarantee.

If you’ve just discovered Japanese Knotweed on your land and are hoping to put your home on the market soon then you should be prepared to pay for your Japanese Knotweed treatment plan in advance. Many potential buyers will not want to purchase property with the knowledge that they’ll have to pay for treatment, and mortgage lenders will also consider their security to be compromised if a treatment or removal plan isn’t in place.

Can I get rid of Japanese Knotweed myself?

You should not attempt to get rid of the Japanese Knotweed yourself if you are hoping to sell your property soon. DIY attempts at removing or treating Japanese Knotweed are rarely successful, but even in the cases where they are, homeowners are still legally bound to mention that the plant has affected the property. When the buyers’ solicitors inevitably enquire about the treatment or removal plan that has been put in place, they will not be satisfied with a DIY solution. Ultimately, regardless of how effective the treatment was, the homeowner will have to pay for a treatment plan in order for the buyers’ mortgage lender to agree with the sale.

How long does it take to get rid of Japanese Knotweed?

It can take years to remove Japanese Knotweed completely from a property. Even when a treatment plan has been completed, the seller of a property will have to mention Japanese Knotweed has affected the property on the TA6 Property Information Form.

The TA6 was recently updated to include a secondary question, for those answering ‘Yes’ to Japanese Knotweed question. This section gives the seller the opportunity to attach any paperwork related to their Japanese Knotweed treatment plan.

Completely removing the Japanese Knotweed from your land before you put the property on the market will put you in the best position to make a quicker sale, but you will always have to mention the historical presence of the plant. Having the necessary paperwork to back up the work will expedite the sale of the property and remove a pain point for any potential buyer who has reservations about dealing with a property affected by the plant.

What can I do if my neighbour has Japanese Knotweed?

If you’ve discovered Japanese Knotweed on your neighbour’s land then you may be worried that this could affect the sale of your house. When property surveyors assess a home, they can perform a cursory visual check of the boundaries. They might not specifically look out for Japanese Knotweed unless they suspect that your property is at risk, however, if they do discover the plant growing close to the border of your property then they will note this down and this could affect the valuation of your home.

The first thing that you should do is talk to your neighbour about the problem. It may be the case that they are unaware of the plant and may appreciate you warning them about it. This conversation may prompt them to take action, however, if your words are ignored then you can approach the matter more formally, with a view to informing the authorities and filing a Community Protection Notice to force them to deal with the infestation. You can sue your neighbour for failing to control the spread of Japanese Knotweed on their land, however, this will unlikely help you sell your home any quicker.

Can you sell a house with Japanese Knotweed at auction?

You can sell a house with Japanese Knotweed at auction; however, you will still be legally required to inform potential buyers of the invasive plants on the land. Prospective buyers at auction are often much more open to purchasing properties with issues such as Japanese Knotweed, however they are only likely to bid if they are fully aware of the problems involved and the amount of additional investment required to make it sellable in the future.

Despite the current infestation and the costs needed to remedy it, cash buyers will see the value in your property, however you may still need to set the reserve price much lower than the value of your home in order to pique their interest. Generally speaking, auction prices for properties start at 15% below their value, depending on the severity of your Japanese Knotweed infestation you may need to start 25% lower. Once the bidding starts, you may find that the property goes for more than you expect, however the nature of the auction process means that there are never any guarantees.

Can you sell a property with Japanese Knotweed to a cash buyer?

Selling your property with Japanese Knotweed to a cash buyer is another option open to homeowners looking to sell their affected property quickly, however, this can come with its own set of drawbacks. Estate agents often have a number of cash buyers on their books who are looking to make a quick investment, however these people will only strike a deal if it’s in their interest. They will rarely agree to a price of more than 30% below the market value of the property (before devaluation from Japanese Knotweed).

Finding a cash buyer who is willing to pay closer to the market value of the home may take more time, and there will likely be little guarantee that any new sale will stick, leaving you in an uncertain position which certainly isn’t ideal if you are already involved in an ongoing property chain. Cash buyer companies specialising in properties affected with Japanese Knotweed are hard to find, and those that are willing to buy the property may do so at a price much lower than any auctioneer’s suggested reserve price.


If you’re trying to sell a property with Japanese Knotweed and are unsure about what your options are then you can get in touch with us for guidance. Call us direct on freephone 03335 777 888 or use the contact form on the right to get started.

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Getting A Mortgage With Japanese Knotweed

The discovery of a Japanese Knotweed infestation can make selling a house a difficult proposition, this is largely due to the historically cautious approach that mortgage lenders have taken to homes affected by the plant. Whilst it may still be possible to get a mortgage on a property with Japanese Knotweed from some lenders, you may find that you will have to take some extra measures in order to prove to the bank that their money is safe with you.

How do you get a mortgage on a home with Japanese Knotweed?

You can get a mortgage on a home with Japanese Knotweed with a selection of mortgage lenders, however in order to so you may need to prove that a professional Japanese Knotweed treatment plan is in place first and typically will have an Insurance Backed Guarantee. Depending on the severity of the infestation, the mortgage lender may ask you to put down a higher deposit or could even charge you more interest in order to balance out the perceived risk of the plant.

How can Japanese Knotweed affect you getting a mortgage?

Japanese Knotweed can negatively affect your ability to get a mortgage. The plant has been singled out by both the Royal Institute of Chartered Surveyors (RICS) and the government as an invasive plant that, if allowed to grow unchallenged, can cause structural damage to buildings, outbuildings such as greenhouses and garages, and disrupt paving and tarmac surfaces. It can also cause damage to underground systems like water and sewage pipes.

After a landmark decision in 2010 by a mortgage lender to not grant a mortgage to a home affected by the plant, lenders quickly put a variety of policies in place to prevent mortgages being given to those who are planning on purchasing properties affected by the plant. Thankfully, some mortgage lenders have relaxed their policies regarding Japanese Knotweed, but there are still some who will refuse to lend unless it can be proven that the Japanese Knotweed has been treated properly.

What do mortgage lenders base their Japanese Knotweed policies on?

Mortgage lenders base their Japanese Knotweed policies on one key resource that is worth reading up on if you are considering buying or investing in a property with Japanese Knotweed: the RICS’ Information Notes called Japanese Knotweed and residential property. This paper was written in 2012 as guidance for Chartered Surveyors to be able to assess the risk factors surrounding Japanese Knotweed and how it can affect properties.

The RICS guidance sets out a framework for risk assessment of Japanese Knotweed infestations. The severity of the infestation is divided into four different categories which are as follows:

4: Japanese Knotweed is within 7 metres of a habitable space, conservatory and/or garage, either within the boundaries of this property or in a neighbouring property or space; and/or Japanese Knotweed is causing serious damage to outbuildings, associated structures, drains, paths, boundary walls and fences and so on.

Further investigations by an appropriately qualified and/or experienced person are required.

3: Although Japanese Knotweed is present within the boundaries of the property, it is more than 7 metres from a habitable space, conservatory, and/or garage. If there is damage to outbuildings, associated structures, paths and boundary walls and fences, it is minor.

Further investigations by an appropriately qualified and/or experienced person are required.

2: Japanese Knotweed was not seen within the boundaries of this property, but it was seen on a neighbouring property or land. Here, it was within 7 metres of the boundary, but more than 7 metres away from habitable spaces, conservatory and/or garage of the subject property.

1: Japanese Knotweed was not seen on this property, but it can be seen on a neighbouring property or land where it was more than 7 metres away from the boundary.

Since being published, most major mortgage lenders have cited the information paper as the driving influence behind their policy-making, a decision which has been criticised during a government assessment of the topic in May 2019. Unfortunately, as there has been no further updated edition of this Information Paper, mortgage lenders have no choice but to continue to use it as a reference for their policies.

What are mortgage lenders’ policies on homes with Japanese Knotweed?

Mortgage lenders take varying approaches for their policies regarding homes with Japanese Knotweed, unfortunately, the majority of them currently err on the side of caution. This position may change when more research is conducted into the effect that Japanese Knotweed has on properties.

Below you’ll find the current stance that major UK mortgage lenders are taking on properties affected by Japanese Knotweed as of the time of writing:

Nationwide Building Society

Nationwide Building Society treat properties affected by Japanese Knotweed with caution. If the plant is within 7 metres of the property’s boundary then a ‘specialist report’ should be obtained by the buyer, as well as an insurance backed eradication plan with a 5-year warranty against re-appearance of the plant.

If the plant is more than 7 metres away from the boundary of the property, then Nationwide will still require written confirmation that the buyer is aware of the Japanese Knotweed and the consequences inherent if the plant gets closer to the property.


The valuers at Santander are trained to spot Japanese Knotweed, if this happens, they will ask for a specialist survey to be undertaken by a accredited specialist. If the plant is within 7 metres of the property then they require the plant to be completely removed by a professional who can offer an insurance backed policy against its return.

HSBC/First Direct

HSBC also use the RICS’ 7-metre rule as guidance for their lending policy on Japanese Knotweed, however their requirements for those seeking a mortgage is unclear:

“We can only lend if we are provided with a treatment schedule and a completion certificate confirming that the weed has been eradicated that there is a guarantee of at least 10 years in place.”

Metro Bank

Metro Bank lends to those buying properties graded in Categories 1 and 2, however they take a stronger position against homes in Categories 3 and 4. For those properties, the bank requires an insurance backed Japanese Knotweed treatment plan to be put in place by a firm approved by either the Property Care Association (PCA) Invasive Weed Group or the Invasive Non-Native Species Association (INNSA). The bank will not release funds until the plan has been fully paid for and guaranteed for 5 years.

Yorkshire Building Society

Yorkshire Building Society appraise each property on a case by case basis; however, they may ask you to fund a specialist report to find out more about the infestation. If they’re not happy with the results then they may choose not to lend. They strongly recommend anyone borrowing on a home with Japanese Knotweed to get an insurance-backed treatment plan in place.

Lloyds Bank/Halifax/Ulster Bank

Lloyds and its associated banks require a specialist report outlining the costs of remediation, these findings will impact the valuer’s decision on the amount of money that can be lent. If it’s determined that the Japanese Knotweed poses a structural threat to the property then no money will be lent.

Royal Bank of Scotland (RBS)

RBS is vague with its response to this issue, stating that their valuers take a number of factors into account when assessing how a Japanese Knotweed infestation can affect a property, including marketability, mortgageability and insurability. Like other banks, they base their policies on the current RICS guidance.

Leeds Building Society

Leeds Building Society requires an ‘environmental search’ to be obtained if Japanese Knotweed is found on the land. They will refuse to lend if they consider the infestation to a threat to ‘the property &/or future saleability’. Their policies are based on recommendations made by environmental specialists and current legal/insurance advice.

The Cambridge Building Society

This society takes a zero-tolerance stance on lending to homes with Japanese Knotweed present on the land, they will also refuse to lend when the plant is within close proximity to ‘the security property’.

Coventry Building Society

When applying for a mortgage you don’t need to inform this bank about Japanese Knotweed if it falls between Category 1 or 2 of the RICS’ risk assessment. If the property falls within Category 3 or 4 then you will need to inform them about it, which will likely make lending unacceptable.

Furness Building Society

This building society bases their lending decision purely on valuers’ comments alone, they don’t give any further guidance than this.

Hinckley & Rugby Building Society

Similarly, this building society bases its decisions on their valuers’ comments.

The Loughborough Building Society

Loughborough Building Society make explicit reference to the RICS guidance in reference to their policy-making decisions. In cases where the Japanese Knotweed is within the property boundaries (Categories 3 and 4) they require a report, treatment plan by a PCA-accredited firm and a guarantee on all remedial works. They also say that they may decline a mortgage even if the property is in Category 1 or 2. If the plant is seen to be a significant threat to the property by the valuer the, no money will be lent.

Newcastle Building Society

This building society require further investigations to take place if the property is assessed as being in Category 3 or 4, this must be undertaken by a PCA-accredited firm. Ay remedial works done must be insurance backed for 10 years, be ‘property specific and transferable to subsequent owners and mortgagees in possession’.

Post Office / Bank of Ireland

The Post Office and Bank of Ireland expect their valuers to make their decisions based on the RICS guidance. If the Japanese Knotweed is deemed to less than a ‘safe distance’ from the property itself then they will ask for proof of either remedial work having been completed, or that a Japanese Knotweed treatment plan is in place.

The bank will also take into consideration the valuers’ opinion on the ‘marketability’ of the property, which suggests that they may choose to decline mortgages if properties are considered to be unsellable because of the infestation.

Bath Building Society

This building society operates with the RICS’ 7-metre rule as their guiding principle. If the Japanese Knotweed is within 7-metres of the building itself then they require a specialist report, followed by proof that remedial works are being undertaken by a PCA-accredited firm.


TSB have guidance related to each Category of the RICS’ risk assessment. For Category 1 infestations, no action is required on the part of the mortgage applicant unless the valuer recommends otherwise. Category 2 cases should be reviewed on individual merits by the valuer. In both Categories 3 and 4, a full report and treatment plan must be undertaken by a firm accredited by either the PCA or the INNSA. All treatment works must come with a 10-year, property-specific, transferable guarantee.

TSB will not lend in cases where Japanese Knotweed is present on neighbouring land and also poses a threat to the property in question.

Will lenders’ policies on Japanese Knotweed change?

Most lenders have said that their policies on Japanese Knotweed will change when the RICS’ guidance has been updated accordingly. Despite the government openly criticising how the ‘7-metre rule’ was arbitrarily decided and is now wielded as a ‘blunt-force’ instrument, there has been no official update to these guidelines. It is likely that the policies laid down by mortgage lenders will remain unchanged until the RICS changes their stance on Japanese Knotweed and how it affects properties.

How do you remove Japanese Knotweed if you can’t get a mortgage?

If you can’t get a mortgage or remortgage your existing home because of a Japanese Knotweed infestation then you may need to remove the infestation first. Bear in mind that it is always best to consult a PCA-accredited removal firm to deal with your Japanese Knotweed, as most mortgage lenders will still not deal with you unless you have an insurance backed guarantee of at least 5 or 10 years.

Japanese Knotweed removal can cost thousands of pounds, depending on the severity of the infestation, but this is, unfortunately, a price that must be paid in order to deal with mortgage lenders. Despite the guidance laid out by the RICS there have been some cases where surveyors have missed Japanese Knotweed, which has led to buyers being refused mortgages or being faced with costly removal fees.


If you’ve discovered Japanese Knotweed on your land, or have found that you have been missold a property that is infested with the plant, then we may be able to help you progress a claim for the cost of removing it, and pay compensation for any reduction in the property value. Get in touch using the contact form on this page or call us freephone on 03335 777 888

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Dormant Japanese Knotweed

Japanese Knotweed is a rhizomatous plant, meaning that it has a modified stem system that grows underground (much like a tree’s roots), which can render it dormant for extended periods, making it practically invisible to the naked eye from above the system. Unlike a tree’s roots, however, each rhizome is capable of producing new nodes and sending shoots up to the surface to create a new plant.

How does Japanese Knotweed remain dormant?

Japanese Knotweed remains dormant thanks to its rhizome system, which is both an efficient means of reproduction and survival. Throughout the spring, new shoots quickly develop into mature plants (up to 3 metres tall), whose broad, shield-shaped leaves capture energy from the sun and send nutrients down to the rhizome for storage. During autumn and winter, when there is not enough light or warmth for the plant to survive above ground, the plants die off and the rhizome network remains dormant until the following spring when new shoots can be sent back to the surface.

This rhizomatous system is not unique to the plant, many other common weeds and flowers in the UK have developed the same feature as a powerful tool to thrive, without relying solely on their traditional form of reproduction. Japanese Knotweed’s rhizomatous nature, and its ability to remain dormant, are the reasons why it can be such a heavily resource-consuming plant to eradicate.

How long can Japanese Knotweed stay dormant?

Japanese Knotweed can stay dormant for as long as 20 years, according to the Environment Agency’s Knotweed Code of Practice. Although this document has now been labelled as out of date by the Government, this number matches up with what other Japanese Knotweed treatment agencies have reported. Unfortunately, there has been no scientific study to back up this anecdotal evidence yet.

Can Japanese Knotweed become dormant after being treated?

Japanese Knotweed can be forced into a dormant state with the use of glyphosate overdosing or residual herbicides. Unqualified and unaccredited firms may use these methods to deliver a short-term result at a cheaper price to property owners who want the plant quickly eradicated. Unfortunately, the use of these techniques can be damaging to the environment and ineffective in the long term. Such treatment causes the plant to die back for a season or two, whilst the rhizome system remains dormant underground recovering from the chemical attack. When the right conditions present themselves, the Japanese Knotweed will return from dormancy and continue to grow as before.

Professional, PCA-accredited Japanese Knotweed removal firms will use legal glyphosate treatments within the recommended doses and time periods. They will not promise a short-term fix to an infestation and will be honest about the length of time that will take to get rid of the plant (which can vary depending on the severity of the infestation). PCA-accredited Japanese Knotweed treatment plans can take several years to complete, as firms must return to the site to apply the chemicals after each season to ensure that any new growth is kept to a minimum until the plant is permanently eradicated. This is why trusted Japanese Knotweed specialists provide insurance-backed guarantees so that the property owner can trust that the infestation will be irrevocably terminated.

How far can Japanese Knotweed spread whilst dormant?

Japanese Knotweed will not spread whilst it is dormant, either above ground or underground. The plant does not receive any nutrients from above the ground whilst it is in a state of dormancy, leaving it with no energy to spread further. However, it is possible for the plant to be inadvertently spread if the ground it is sitting in is disturbed. If rhizomes are disturbed by a gardener or heavy machinery, it is more likely that the plant will come out of dormancy to grow and spread once more.

How can you tell if a property has dormant Japanese Knotweed?

You can tell if a property has dormant Japanese Knotweed by inspecting the grounds for evidence of dead stems. When the plant dies back during the late autumn and winter months, its stems turn brown and brittle but remain above ground, which acts as a protective layer for the rhizome system against the damaging effects of frost. As the leaves fall off the plant during this period, the stems turn from their usual green speckled-purple to a brown-orange colour. These canes can often remain standing throughout the winter months, whilst the plant remains dormant and are the best indicator that a property has dormant Japanese Knotweed present.

Can you build on land with dormant Japanese Knotweed?

It is possible to build on land with dormant Japanese Knotweed, however before doing so certain precautions must be taken to ensure that the plant is not inadvertently spread throughout the development site or, worse still, off the site altogether. Doing so can result in a hefty fine or even custodial sentences for those responsible. For this reason, building developers will need to put a management plan in place to ensure that the spread of the plant is controlled, and the plant will not return from dormancy after construction has been completed to affect others at a later date. There are a number of Japanese Knotweed removal techniques open to developers, depending on their budget and the size of their site.

Do surveyors check for dormant Japanese Knotweed?

RICS surveyors do not specifically check for dormant Japanese Knotweed unless they have been given a reason to. In the RICS guidance, there is a brief mention of the plant’s ability to remain dormant (especially after treatment), however, its appearance whilst in this state is not noted.

The extent to which surveyors should be found negligent for missing Japanese Knotweed has been the subject of some contention, usually, they are only found to be so if they could have reasonably found the plant within the course of their survey. Surveys can come in different forms, for example, the RICS note that a mortgage evaluation might not focus enough on the land surrounding the property to make the discovery of Japanese Knotweed possible.

Is it worth buying a house with dormant Japanese Knotweed?

Buying a house affected by Japanese Knotweed (even in its dormant state) is not recommended unless a PCA-accredited, insurance-backed treatment plan has been put in place first. Even if the plant does not pose a threat to any structure, many mortgage lenders will not deal with properties that have the plant present, regardless of if a treatment plan is in place or not. Although some lenders have relaxed their stance on the invasive plant over the years, many still have a zero-tolerance policy concerning properties affected by Japanese Knotweed.

Can I sell a house with dormant Japanese Knotweed?

It is possible to sell a house with dormant Japanese Knotweed; however, it is not advisable to do so without stating clearly that the property is affected by the plant in the TA6 Property Information Form. Even though it might be tempting to make the assumption that the plant has been permanently eradicated, unless you have an insurance-backed guarantee saying as much, the Japanese Knotweed is technically still affecting the property and will adversely impact the value of your home. Choosing to gamble that the plant will remain dormant, and selling your property without mentioning it, could lead to you being sued later on.

What happens if I am missold a house with dormant Japanese Knotweed?

If you are missold a house or property with dormant Japanese Knotweed then you may be able to sue the seller for misrepresenting the property. In most cases, the property owner will have to fill out a TA6 Property Information Form declaring whether Japanese Knotweed is present on the land or not (they also have the option to respond with ‘Not Known’). If you can prove that their answer on this form was a lie and that they reasonably should have known about the Japanese Knotweed, then you should be able to claim back the discrepancy in the price that you paid for the property, as well as the costs of removing the plant.


If you’ve discovered Japanese Knotweed on your property after being told otherwise, or have found that a neighbour has allowed the plant to spread onto your land, we may be able to recommend support to help you claim back the costs of treatment. Call us today on freephone 03335 777 888 or send us an enquiry using the contact form, to see if we can help you with your Japanese Knotweed problem.

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