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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5% of houses in the UK are affected by Japanese knotweed

This figure has increased significantly in recent years – with the exponential growth of Japanese Knotweed this means 1 house in 20 could be reduced in value by up to £100,000!

At a CPD events run for surveyors, an experienced gentleman stated that he had never come across Japanese Knotweed on any property he had surveyed – this really blew us away as we see it every day. It really highlights the problem that many professionals cannot easily identify Japanese Knotweed. The most common places it can be found are on brownfield sites and areas where fly tipping has occurred. Another common place is at the back of terraced houses and where there are badgers and foxes regularly travelling through a person’s garden. Also houses and land that are located near railway lines and waterways are particularly common, Network Rail having planted Japanese Knotweed along the banks of the railway lines to kill other weeds not knowing that this weed would literally take over; and waterways spread Japanese Knotweed downstream.

The reason why we see a much higher concentration of Japanese Knotweed in these areas is due to the way it reproduces. In the UK the seed is not viable, so although it produces seeds these will not produce viable plants, although a male plant was discovered in the UK in late Autumn 2020 and experts are looking into this. The plants therefore reproduce from cuttings. There are two types of cutting to propagate a new plant; a stem and a rhizome cutting. The stem has to have two nodules, one to become the root and one to become the new shoot. However, if a small piece of the rhizome is taken – and this can be as small as your fingernail – this will produce a new plant. For these reasons we would never recommend strimming Japanese Knotweed or trying to excavate it by yourself as is can be very easily spread, and as we know Japanese Knotweed is restricted waste and must be disposed of at prescribed sites.

If, as a member of the public, you spread Japanese Knotweed you can face a £2,000 fine and, if you are a business, it can be a £20,000 fine with 6 months in prison. Also, if you allow the Japanese Knotweed to grow from your garden into a neighbour’s garden then they can bring a civil case against you for depreciation of the house, loss of enjoyment and even stress! Claims in excess of £30,000 are not uncommon, and we have seen a successful claim in 2019 for £106,000.

Treatment plans are available with an Insurance Backed Guarantee which will satisfy banks offering mortgages and remortgages. Most lending facilities now have Japanese Knotweed safeguards and will not lend unless an insured treatment plan is in place. Japanese Knotweed removal can be extremely expensive and so most opt for a treatment plan.

Surveyors may be the most common professionals to be litigated against if the Japanese Knotweed has not been identified within their survey, and will be attributed to professional negligence. With typical devaluations being 10%+ of the value of the property, this can cause a massive problem when trying to sell your house if you do not have the right people on board to assist you.

Japanese Knotweed Agency offers free support and advice for those affected by Japanese Knotweed. Call freephone 03335 777 888 or visit website www.japaneseknotweedagency.co.uk

Polygonum bidwelliae

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Can You Build on Land with Japanese Knotweed?

Japanese Knotweed can cause financial difficulties to both homeowners and building developers, especially when plans have been made to build on land that is home to the invasive plant. Despite Japanese Knotweed now being well-documented, homeowners and builders alike are still being presented by new scenarios which require legal guidance. Whilst there have been several precedents set in recent years which have solidified certain aspects of Japanese Knotweed law, it’s not uncommon for landowners to be unsure of where they stand when it comes to building on land with Japanese Knotweed.

Can new buildings be developed on land with Japanese Knotweed?

New buildings can be developed on Japanese Knotweed infested land, however, in order to legally do so, the presence of the plant should be declared and accounted for as part of the planning process. There have been several cases in recent years where building developers have chosen to ignore or hide the Japanese Knotweed on their land, in order to avoid stalling their construction and to hasten the sale of the finished properties.

Unfortunately, building developers are not currently required to fill in the TA6 property form that is a standard part of the process in home exchanges, allowing them to lie about Japanese Knotweed. This legal loophole has allowed new build developers to complete their work and then sell to homeowners who are unaware that they are buying a property affected by the invasive plant. Whilst there is no requirement for a TA6 property form, homebuyers can protect themselves by asking their conveyancing solicitor to ask the developer about any history of Japanese Knotweed on the site.

It is important to note that a Japanese Knotweed trained person can identify Japanese Knotweed, the route of its growth and its age!

Is a Japanese Knotweed survey required before building development takes place?

A Japanese Knotweed survey is not required on land before development takes place, however if there’s a suspicion that the plant might affect the land then a survey could avoid time being wasted and potential money being lost. Japanese Knotweed surveys can be undertaken by ecological experts or chartered surveyors and will either confirm or deny the presence of the plant on the land. In addition to identifying Japanese Knotweed, a survey can help define the extent to which the plant affects the property, this could then impact any control plans that might be put together.

For example, if the Japanese Knotweed is only discovered in an isolated patch, then it may be possible for this portion of land to be demarcated and for construction to continue regardless. Conversely, if the infestation is found to be widespread, then controlled excavations might need to be conducted in order to properly remove any remnants of the plant from the land before building takes place. Unfortunately, in some cases, surveyors miss Japanese Knotweed, leading to a sale going through and a buyer being left out of pocket.

Is planning permission required to build on land with Japanese Knotweed?

Planning permission is required before most kinds of building development takes place, this includes land with Japanese Knotweed. Most councils will have policies in place concerning Japanese Knotweed, and might also be aware of where the plant has already been discovered. Ignoring the presence of the plant and choosing to move soil contaminated with Japanese Knotweed is a criminal offence under the Wildlife and Countryside Act 1981, which can lead to a heavy fine and even imprisonment.

In cases where the owner of the land is aware of Japanese Knotweed on their own land, then they may need to make specific planning conditions alongside their application to show that they have factored the plant into their plans. Planning conditions set out how the Japanese Knotweed will be controlled throughout the building development. This will include an assessment of control options, criteria for the completion of control measures and details on how those working on the site will prevent the further spread of the Japanese Knotweed.

Should Japanese Knotweed be removed before building starts?

Japanese Knotweed may need to be removed from land before building commences, depending on the severity of the infestation. This plant has the capability to grow up to 3 metres deep and 7 metres laterally from its visible point above ground, so in the case of large infestations, underground rhizome systems can sometimes be spread much further than may first appear. Due to the plant’s seasonal growth patterns, and tenacious growth characteristics, the entire removal of the Japanese Knotweed could be required in order to ensure that it does not disturb foundations, or exploit any weaknesses whilst searching for a route to moisture and sunlight.

There a number of laws that control the removal of Japanese Knotweed contaminated waste, additionally, building contractors are subject to more regulations that private landowners. In order to avoid large fines, developers should ensure that only registered waste carriers are used to dispose of any contaminated soil. It’s illegal to dispose of Japanese Knotweed along with other soil, and it’s also recommended to inform the chosen waste disposal site before dropping off the controlled waste.

Will Japanese Knotweed grow through new builds?

Japanese Knotweed has been known to grow through new builds, however, this usually only occurs in circumstances where an infestation is particularly large. Although the destructive ability of Japanese Knotweed has been exaggerated by some media sources, the plant still remains a force to be reckoned with. In a recent report by the Science and Technology Committee, experts from across the industry gave their findings on how the plant affects buildings, and whilst many agreed that it was capable of damaging buildings, it was admitted that this damage was no worse than what could be done by common trees.

With that being said, it was noted that whilst trees such as buddleias could feasibly do more damage to property than Japanese Knotweed, these trees were much easier to remove. It was agreed that whilst the destructive abilities of Japanese Knotweed had been overblown by some in the industry, their hardiness and resistance to traditional forms of removal had not been understated.

How much could a property be devalued by, if it’s built on Japanese Knotweed?

A property can be devalued by 10% up to 100%, if Japanese Knotweed is discovered on the land it is built on. In extreme cases, a home can be almost completely devalued by Japanese Knotweed, such as in the case of the Jones’, a family in Bedford who were told that their new build had dropped in price from £350,000 to £50,000, after having lived there for one month. It should be noted that, besides the devaluation of the property, there might also be additional costs incurred as a result of building on land with Japanese Knotweed.

For example, if the seller attempts to lie about the presence of Japanese Knotweed on their land, then they could be sued for misrepresentation by the buyer. In a survey of 100 individuals who had been affected by Japanese Knotweed (undertaken by the Crop Protection Association), 15% had seen a property deal through as a result of the discovery of the plant, whereas 20% saw a drop in their house value and 10% were forced to pay compensation of some kind as a result of finding the plant on their land.

Do you have to declare Japanese Knotweed after it’s been built on?

Property owners do not have to declare Japanese Knotweed after building on the land if they are planning on staying on the property, however, they should make any potential buyer of the property aware about the presence of Japanese Knotweed, otherwise, they may be liable for misrepresentation. Any person choosing to live on land affected by Japanese Knotweed will be legally responsible for ensuring that it does not spread to neighbouring properties. If the plant is allowed to spread, whether during the construction process or by any other means, the owner of the land will be liable to fines or imprisonment.

Is it possible to build on land with Japanese Knotweed while it’s being treated?

It is possible to build on land with Japanese Knotweed while it is being treated, depending on the size of the infestation, the choice of treatment and the planned development. Unfortunately, in cases where there is a concentrated infestation over a small area of land, it may be impossible to undergo construction until the Japanese Knotweed has been dealt with. A thorough Japanese Knotweed survey, in association with a set of planning conditions, can help to decide whether the development will be able to begin before, after or during the treatment of the plant.

When a Japanese Knotweed infestation of 4 acres was discovered before work was due to be undertaken on the Olympic Park for the 2012 games, it was decided that treatment and removal of the plant could be managed in tandem with construction. Despite the 4 hectares comprising less than 2% of the entire park, the overall treatment ended up costing £70 million and took years to complete. Due to the strict limitations placed on the movement of Knotweed contaminated waste, the Environment Agency, London Development Agency and Olympic Delivery Authority devised a varied approach including glyphosate treatment, burning and burial beneath a protective membrane.

Will Japanese Knotweed deter developers from buying land to build on?

The presence of Japanese Knotweed will likely act as a deterrent for most developers who are planning on building on the land. Whilst Japanese Knotweed is not treated with the same level of outright fear as it once was, its presence devalues property and can cause delays in the sale of the land. In order to build on land that has Japanese Knotweed, developers should set out planned conditions, so that they do not inadvertently spread the plant, and they should also inform any future buyers that Japanese Knotweed is present, regardless of if it has already been treated.

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A Guide to Reporting Japanese Knotweed

After positive identification has been made of any Japanese knotweed infestation, it becomes necessary for other parties to be notified of the problem so that they have the opportunity to respond. In most Japanese knotweed compensation claims, legal action cannot be pursued until all parties have been informed of the infestation. Notifying authorities of Japanese knotweed on public land can also help to prevent the ongoing spread of the plant.

Is it illegal to not report Japanese knotweed in your garden?

It is not illegal to have Japanese knotweed in your garden, or on your land. If you have discovered the plant on your land then you are under no legal obligation to notify anyone about it or even treat the plant. You are, however, responsible for ensuring that the plant does not spread into neighbouring land, whether it be privately or publicly owned. You cannot see its growth and spread underground and if you are aware and do nothing, you leave yourself at risk of a claim being made against you.

Is Japanese knotweed notifiable?

Japanese knotweed is not a notifiable plant. Unlike some other invasive plants which require immediate action on the part of the landowner, the government does not have to be informed about the infestation, nor to your neighbour’s. You don’t have to report Japanese knotweed on someone else’s land either, however, you may choose to do so if you feel like the plant could enter your land, or if you feel like it is at risk of further damaging the environment.

When should you report Japanese knotweed?

You should report Japanese knotweed if you think that it is causing damage to your local environment if you think it might soon enter your property, or even if you think that it might not have been identified yet by local authorities. Although you are not legally required to do so, reporting Japanese knotweed to the appropriate authorities can help the government keep track of the ongoing threat of this invasive plant.

Do you have to notify your estate agent about Japanese knotweed?

You should notify your estate agent about Japanese knotweed on your land as soon as possible. If you’re planning on selling a property with Japanese knotweed then you should be as honest as possible with your estate agent. You will have a better chance to sell your property if the estate agent has access to all the information about it. They are legally obligated to present your home truthfully, so by failing to mention the infestation to them, you may risk endangering any future sale in addition to your business relationship with them.

Do you have to notify potential buyers about Japanese knotweed?

You must notify potential buyers about Japanese knotweed on your land, this is done using the TA6 Property Information Form which is filled out by property owners and given to prospective buyers so that they can have access to all the facts about the property. Failing to answer truthfully on this form can result in a claim of misrepresentation being put against you, and could also lead to a sale falling through, which can have a knock-on effect on any purchase that you might be planning on making yourself.

Must a surveyor report Japanese knotweed?

A surveyor must report Japanese knotweed if they identify it whilst carrying out their work. Regardless of whom is paying them for their services, surveyors have an ethical duty to report any invasive plant they might discover. RICS qualified surveyors are trained to look for Japanese knotweed, especially when they feel that the area that the property is located in is at particular risk of having the plant, there are occasions, however, when they miss it on their survey.

How do you report Japanese knotweed?

If you are planning on reporting Japanese knotweed then you may wish to make a few notes about the infestation before doing so. Whether you are telling the local authority or sending a formal letter to a neighbour or organisation, you are likely to get a better response by providing as much detail about the problem as possible.

For example, you may wish to include an estimate of how much land has been affected by the plant. Depending on where the land is, you could also take photographs of the plants and include these with the exact coordinates of the location. This can be of particular use when you are reporting a Japanese knotweed infestation that is in an isolated location, or along a footpath without any clear landmarks. You could also make a note of whether or not the infestation has been treated, or if it looks like an attempt has been made to remove the knotweed.

How do you report Japanese knotweed on neighbour’s land?

Reporting Japanese knotweed on your neighbour’s land to local authorities is a positive step towards stopping the plant from entering your land, however, it should only be done if you have first formally told your neighbour’s of the infestation.

If they choose to ignore your formal letter, then you’ll have evidence to support your request for a Community Protection Notice (CPN) from the local authority to enforce them to deal with the infestation on their property.

In order to obtain a CPN against your neighbour, it must be proven that they have refused to take reasonable steps to deal with the infestation. Before reporting the Japanese knotweed to any authorities, you should try talking to your neighbour first, it’s possible that you may be able to come to an agreement before having to escalate the matter further.

How do you report Japanese knotweed to your landlord?

You can report Japanese knotweed to your landlord by writing to them with as much detail as possible regarding the infestation. As with most discoveries of Japanese knotweed, it’s best to tackle any infestation as early as possible, to avoid costs of treatment potentially spiraling out of control.

Depending on the lease that you have signed with your landlord, you may find that you are liable for the costs of treatment. In the event of this happening, you may want to investigate the source of the infestation, as there could be a possibility that the knotweed entered from another property, making the owner of that property liable instead.

How do you report Japanese knotweed on neighbouring council land?

You can report Japanese knotweed growing on neighbouring council land by contacting your local authority directly. Local councils are subject to the same knotweed laws as any other organisation; therefore, they are prohibited to allow Japanese knotweed to spread from public land into privately owned land.

Many local councils have electronic systems in place to deal with maintenance requests from citizens. You should make sure to include as much detail as possible in your report regarding the severity of the infestation, as well as any photos you have to back up your claim. The sooner you put this report in, the sooner you’ll get a response; don’t wait for the infestation to get any worse before taking action.

How do you report Japanese knotweed on public land?

You can report Japanese knotweed that you’ve identified on public land by either contacting your local authority via their website or by using the Plant tracker app on your phone. The government actively encourages citizens to submit their sightings of Japanese knotweed, regardless of if it is on neighbouring land or not. As the invasive plant has continued to spread throughout the country, there is now a greater need for members of the public to report Japanese knotweed where possible, in order to curb its ongoing growth.

How do you report fly tipping of Japanese knotweed?

Report fly tipping of Japanese knotweed by calling the Environment Agency on their 24-hour freephone number (0800 80 70 60). Fly tipping any material that contains Japanese knotweed is a criminal offence that can be punishable with up to 2 years imprisonment and an unlimited fine on indictment. The most common reason for the fly tipping of Japanese knotweed is when construction firms do not want to pay for getting rid of the knotweed, this inevitably leads to new infestations rising, which can cost the affected landowner thousands to deal with.

How do you report Japanese knotweed to Network Rail?

You can report Japanese knotweed to Network Rail by calling their helpline (03457 11 41 41) or using their website. A landmark court case in 2017 set a precedent whereby Network Rail had to pay compensation to homeowners in South Wales, who were able to prove that Japanese knotweed encroaching onto their land from railway embankments caused the value of their home to diminish.

Since this case, Network Rail has been forced to spend over £1.2 million in Japanese knotweed treatment and compensation claims, however, some are reporting that they are still responding too slowly to requests. In the case that you do not receive a response from them, or they take a long amount of time to do so, then you may be able to claim compensation against them.

Remember, you do not need to report to Network Rail or any other body if Japanese Knotweed has come from their land on to yours, you can protect yourself by making a claim at any stage.

If you’ve found Japanese knotweed encroaching on your land, and are unsure of who to report it to, then please call us on freephone 03335 777 888, or send us a message using the contact form on our website.

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What Does Japanese Knotweed Really Do?

Over the last decade, Japanese knotweed has developed a reputation for being one of the most aggressive, invasive plants to be currently blighting the country. However, despite the plant’s fearsome reputation, there can still be some confusion as to what it actually does. This article will explain what Japanese knotweed does from two perspectives: environmental and financial. The examples cited here should be considered within the larger context of Japanese knotweed cases, this plant can thrive in all sorts of environments, but no single infestation is the same.

What are the environmental impacts of Japanese knotweed?

Japanese knotweed has a number of physical characteristics which has made it particularly troublesome in the UK, chief of these is the incredible speed that it grows at. Whilst it does die back during winter, its peak growth during the summer can see it growing up to 20cm a day and 1.5 metres in the space of a week. Coupled with its incredible resilience, it’s unsurprising that the government has labelled Japanese knotweed as an invasive threat

Not only does Japanese knotweed grow fast, but it also spreads at an alarming rate. Although the plant does not propagate in the usual fashion in the UK (only the female of the species was imported to Britain in the 19th century), it spreads via an underground root system, comprised of rhizomes. Not only are these roots fast-growing, but they’re also capable of growing from the smallest of fragments, which was one of the driving factors behind the government making it a criminal offence to move soil that has been contaminated with the plant.

Unfortunately, despite the control measures that have been put in place, the spread of Japanese knotweed has continued to the point where the plant is estimated to an infestation for every 10 square kilometres in Britain, according to PlantTracker who produced data that helped build a map showing the spread of Japanese knotweed in the UK.

How deep are Japanese knotweed roots?

Japanese knotweed roots can develop a system that burrows up to 3 metres deep underground and a further 7 metres horizontally from where the plant breaks ground. The depth and complexity of this root system make it a difficult and costly task to remove completely. Whilst digging out the plant is considered to be one of the most effective methods of eradicating Japanese knotweed, the cost and disruption of doing so can be prohibitive to some.

Does Japanese knotweed smell?

Japanese knotweed does not have a particularly distinctive smell. Its scent is not considered to be one of its defining features and does not contribute to its undesirable reputation.

Is Japanese knotweed dangerous?

Japanese knotweed is not poisonous, nor does it pose any physical danger to animals or people. The plant does, however, pose a threat to native plants that are not as well equipped to compete with this foreign element. The environmental impact that this plant has on our own wildlife is often overlooked in favour of the financial costs of treating it. When the plant is allowed to thrive on public waterways or on disused industrial lots, it can quickly stifle the growth of any other plants growing nearby.

What are the financial impacts of Japanese knotweed

Setting aside the environmental impact of this invasive species,  an infestation can have serious financial implications for all involved. Homeowners discovering Japanese knotweed are faced with the knowledge that the value of their home will almost definitely depreciate. Developers who want to build on land with Japanese knotweed may have to completely redraw their plans, as they might have to pay for the complete removal of the infestation before they can go ahead with any construction. For example, plans for developments, in the lead up to the London 2012 Olympics, were delayed when a massive infestation was discovered on the proposed land. Teams spent four years getting the weed under control.

Perhaps most frustratingly, Japanese knotweed infestations can lead to wasted time and the collapse of property chains, which come with their own set of financial pitfalls. For example, often a prospective buyer may spend hundreds of pounds on surveying a property, under the impression that there is no Japanese knotweed present (according to the TA6 property form). On discovering a significant infestation and not wishing to take on the responsibility that comes with treating it, the buyer may drop out of the purchase, but there will be no legal recourse for them to recover the money that they spent on the survey as no form contract would have been signed.

All told, Japanese knotweed is estimated to cost the UK economy £166 million per year for treatment and in property devaluations.

What does Japanese knotweed do to a house?

Japanese knotweed does not necessarily ‘write off’ a house. How the plant affects the property will depend on the severity of the infestation and how close the plants are to the buildings. Although it’s possible to find evidence of Japanese knotweed literally breaking through into homes, this is rare and usually the result of a combination of poor building maintenance and a particularly aggressive infestation. Japanese knotweed’s predominant effect on a house is financial. In the average case of Japanese knotweed discoveries, the value of the property is diminished between 5-20%.

Can Japanese knotweed grow through concrete?

There is some photographic evidence to prove that Japanese knotweed can grow through concrete, however, this has only been noted to happen in scenarios where the infestation is particularly bad and the construction work is particularly shoddy. In extreme cases, Japanese knotweed is also know to disrupt independent structures such as garden sheds, greenhouses, fences. The plant can also slowly break through shoddy brickwork, paving and tarmac.

Can Japanese knotweed damage foundations?

It’s possible for Japanese knotweed to damage the foundations of a house, but this will only happen when infestations are long-established and there are already weaknesses in the building. In very rare cases, Japanese knotweed has been known to break its way through floorboards and skirting boards which can lead to a house being unsellable, as in the case of the Joneses in Broxbourne who were recommended to demolish their entire home. Their property’s value plummeted from £350,000 to £50,000 – a rare example but one which has had an impact on the industry at large.

Can you sell a house with Japanese knotweed?

It is legal to sell a house with Japanese knotweed, however, the invasive plant’s reputation often makes it difficult to sell up when the time comes to it. If you’re attempting to sell a property with Japanese knotweed then you should state that the property has been affected on the TA6 property form. Similarly, if you’re aware that the land has been treated at some point, even if the knotweed has died off, you should still mention it. Failing to mention or lying about your property being affected by Japanese knotweed could lead to a misrepresentation claim being brought against you.

Can you get a mortgage on a property with Japanese knotweed?

You can get a mortgage on a property with Japanese knotweed, but most mortgage lenders will first ask to see evidence of a knotweed management plan being in place. This plan will prove that you have hired a PCA-accredited removal firm to manage the removal of the plant, and will also be insurance backed, so that in the event that the firm goes out of business before the plan is complete, another company will carry on the work. Although some lenders have relaxed their stance on Japanese knotweed, there are some that still refuse to give mortgages for properties affected by it. Re-mortgaging properties that have recently become infested can also be difficult, depending on the lender that you’re dealing with.

Finally, a Japanese knotweed infestation can also be the root of tension and conflict between two parties, whether they’re neighbours, or strangers attempting to negotiate a sale. Due to the potential legal complications that can ensue from the discovery of Japanese knotweed, the plant can also be responsible for undue stress and pressure as individuals attempt to fight their corner without the legal help that they need to succeed. Without legal aid, parties can quickly become trapped in a frustrating back and forth with councils or organisations, this time wasted can only add to the pressure as both parties are aware that whilst the discussion is ongoing, the infestation is being allowed to continue growing.

If you’ve discovered Japanese knotweed on your land, or are currently locked in a dispute related to it, then we may be able to help. Give us a call or send us a message using the contact form, and we’ll get back to you with guidance on how best to proceed

Freephone 03335 777 888

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