The Wildlife and Countryside Act 1981 under section 114(2) (WCA 1981) classifies Japanese knotweed as a controlled plant. Is it illegal to sell a house with Japanese knotweed on it becoming more and more relevant within the UK?

Especially when it can bring the powers of the law to bear upon the owner of the property it encroaches on.

As a homeowner or seller of commercial property, it is not illegal to have Japanese knotweed growing in your property; however, what you should be wary of is the spread of the knotweed to other properties because that is where legal implications apply.

Based on the unprecedented damage this weed plant can cause to property, buildings and the environment, it is only right that as a homeowner you treat the weed plant whilst it is on your property because its spread to adjacent houses may expose you to legal implications that can be costly.

Is it illegal to sell a house with Japanese knotweed on it, is a fundamental qquestion being asked by homeowners?
Is it illegal to sell a house with Japanese knotweed on it, this is a fundamental question being asked by homeowners.

What to do when selling a house with Japanese knotweed in the garden  


Normally, the conveyance process of selling a house is guided by formal laws that impose duties and obligations that must be fulfilled by both parties to the transaction.

On the part of the seller and his agents or any person acting for them in a sale, one of the key duties of such a person is the disclosure of the presence of Japanese knotweed in the property.

The Law Society Property Information Form TA6 which is normally sent by the buyer’s solicitor to the seller of a house requires that important information as regards the house intended for sale is disclosed and this includes the presence of the knotweed.

If you fail to disclose the presence of the knotweed infestation you can be sued by the buyer for misrepresentation and this will attract the payment of damages equivalent to the extent of the financial harm caused to the buyer especially in putting in place measures to treat the knotweed infestation.

Conduct a professional survey and treatment plan report

A survey is best when you want to know the severity of the knotweed infestation on the property and also the costs attendant to the eradication of the knotweed infestation.

Once you have conducted a survey, you should either subject the weed plant to a treatment program that is insurance-backed or honestly presents the report to the buyer so that they are fully aware of the threat of the knotweed on the property.

Additionally, a professional survey and treatment plan report can be used to persuade mortgage lenders to offer loans to potential buyers. Basically, the survey report shows the severity of the knotweed infestation and the amount of money one is likely to use in getting rid of the Japanese knotweed.

Considering that mortgage lenders need to feel secure before lending out any money, the parties to the sale agreement can formally commit to enforcing the treatment plan and this will in return facilitate easy access to the loans.

Make a plan

As a seller of the property, for you to successfully close a deal on a house infested with Japanese knotweed in the garden, it will take a well-worked plan that will convince the seller to finalize the agreement.

Significantly, knowing that most mortgage lenders will not offer loans to a buyer intending to buy a house that is in danger of knotweed infestation, part of your plan as the seller is to secure a professional insurance-backed guarantee for the treatment of the knotweed.

Basically, your plan should work towards securing the interests of any potential buyer because the moment the buyer feels downplayed or misrepresented; they are likely to walk away from the deal.

Negotiate a fair price

Notably, the presence of Japanese knotweed in the garden of a house has a negative effect on the value of the property. Depending on the severity of the knotweed infestation, the property can depreciate from as low as 10% to as high as 30%.

Therefore, to ensure you get a good price on the property, you need to engage the seller professionally and cut a deal that is agreeable between both parties. 

Additionally, as a seller, you may be forced to compromise on the selling price if the presence of the knotweed is severe so that the buyer can use the discounted money to initiate a treatment plan.

Where both parties agree on a certain compromise, it is important to have such information written down and signed by both parties to avoid any future confrontations.

Understand the role of agents

When you entrust other professionals such as estate agents to help you get a good buyer on a piece of property, it is important to know what role each one of those persons plays.

When it comes to the sale of property with knotweed infestation, you cannot escape liability as a seller for non-disclosure of the presence of the weed plant on the property simply because you hired persons to do the job for you. Liability will always be tied down to you.

Therefore, whenever you delegate any duties, ensure that the person doing the work knows what is expected of them from start to finish.

Know whether it is illegal to sell a house with Japanese knotweed on it, is paramount
Understanding why it is illegal to sell a house with Japanese knotweed on it is paramount


The mere presence of the knotweed infestation on a piece of property can send shivers down the spine of purchasers or homeowners. This pesky weed plant can make or break a deal for the sale of a house based on the legal implications attached to the person selling such a property.

Notably, if you know that the property you are dealing with is infested with knotweed, you must make disclosure of this information to the buyer.

Any attempt to mislead the buyer or lie about the presence of the weed plant only exposes you to legal consequences that will subject you to heavy fines.

As a buyer, the presence of the knotweed on a property that you are interested in should not scuffle the deal. However, this does not mean that you waive your rights towards getting a house with a knotweed infestation.

Strive to have an open discussion with the seller on ways you can mitigate the risk of the weed plant, for instance, by demanding that a management plan is put in place that has an insurance-backed guarantee before you finalize the transaction.

Want to know more about whether is it illegal to sell a house with Japanese knotweed or not?

Knotweed Removal aims to provide the most up-to-date information, help and advice for YOU to make informed decisions. If you are unsure or uncertain about how to proceed, please reach out to us and we will gladly come back and advise you as best we can.

Governmental advice can be found here and the UK law covering the removal of Japanese Knotweed as stated under the Wildlife and Countryside Act 1981 can be found here.

The best means to contact us is via our email –

Do not forget we have a library of blogs covering many areas relevant to Japanese Knotweed, our free downloadable How-to Guides and Product Reviews on the latest methods being employed to eradicate or remove Japanese Knotweed.

Knotweed Removal, UK

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Roundup Fast Action Weedkiller Pump 'N Go Ready To Use Spray, 5 Litre
  • Fast action ready to use weed killer that kills the weeds and roots with visible results in 1-2 days
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  • Children and pets need not be excluded from treated areas (once dry)
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  • Degraded in the soil by micro organisms
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Roundup Tough Weedkiller, Ready to Use, Spray, 1 Litre
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  • Includes special guidance for treatment of tough and woody seeds
  • Children and pets need not be excluded from treated areas (once dry)
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Elixir Gardens 360 g/l Glyphosate Commercial Industrial Strength Weed Killer | Treats up to 3332 sq.m | Concentrated Herbicide/Weedkiller | 2 x 1 Litre Bottle + Measuring Cup & Gloves
  • Quickly & effectively clears areas of weeds and unwanted vegetation.
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