When you consider buying or selling a property with Japanese knotweed it pays to do some due diligence in order to protect you and others from damage to your property or worse still, legal implications.
A Japanese knotweed infestation should be a major cause of concern when it is growing in adjacent lands or present from a certain distance from your property.
The three main factors that make this weed plant dreaded is the ability to cause destruction to property, the ability to dominate and area where it starts to grow and its ability to survive even in extreme conditions.
Buying or selling a property with Japanese knotweed is a different ball game because of the many issues involved before the deal is finalized and it is on this footing that we are going to discuss the underlying issues that you should be wary of.

Property market
Generally, Japanese knotweed infestation affects property sales in a big way.
Foremost, mortgage lenders are often reluctant to loan their money on properties that are infested with Japanese knotweed unless it is shown that there is a proper treatment plan which has an insurance guarantee for a certain period of time.
Based on the foregoing, coupled with the negative impact that Japanese knotweed infestation has on the property, this can account for up to 10-15 per cent of the property’s fall in value.
Notably, the bigger the infestation of the weed plant the higher the depreciation rate. Therefore, whether you are buying or selling a property, you can rest assured that the presence of the weed plant will have a certain impact on the value of the property.
What a purchaser of property needs to do when purchasing a property with Japanese knotweed.
Conduct a Japanese knotweed survey and Management plan report
The key reason for conducting a professional Japanese knotweed survey and management plan report is to help you identify the issues and the necessary costs that it will take to completely get rid of the Japanese knotweed from your property.
A Japanese knotweed survey will also help you to know the extent of damage caused to the building; sometimes the damage may not be visible to the common eye until the expert investigation is done, for instance, underground damage to structures such as drainage pipes can only be revealed by a professional survey.
Equally, a survey will help in understanding the rate at which an infestation is likely to spread from one area to adjacent lands. This will further enable you to initiate prompt treatment measures.
- Liabilities
As a purchaser, you need to know the type of liabilities a Japanese knotweed infestation poses to the property since after the sale agreement is finalized you will be in possession of the property and you will bear all the responsibilities that come with its ownership including preventing the possible spread of the weed plant to neighbouring lands.
Notably, after understanding the liabilities and as a purchaser you opt to continue with the transaction, it will be wise if you entered into a negotiation with the seller to offer you a discount on the selling price so that you can channel the funds towards a treatment plan.
- Protect your interests
As a purchaser, you get to bear the bigger responsibility once the ownership passes to you; therefore, it is important that you protect your interests at all costs. This includes ensuring that you are not duped into accepting a cheap eradication plan by the seller of the property.
You need to ensure that if this is the case, the work is done professionally with an insurance-backed guarantee. If this is not the case, then you will not be getting a fair deal and it is only wise if you walked away.
- Close the deal only if you must
The mere presence of Japanese knotweed should not scupper your deal to purchase property but in instances where it is evident that you are not getting a good deal that will enable you to facilitate the treatment of the property with Japanese knotweed infestation.

What a seller must do when transacting on property infested with Japanese knotweed
- Disclosure
As a seller, it is your legal duty to disclose the presence of Japanese knotweed in the property that you intend to sell to any potential buyer.
When selling property, the process must be done in good faith and parties need to disclose any detail that may be significant in helping another party make a decision as regards the transaction.
As a seller, if you do not disclose the presence of the weed plant on the property, a seller can successfully maintain a claim against you for damages and compensation so that he can treat the Japanese knotweed infestation.
The buyer is at liberty to maintain a court action for misrepresentation on the seller once disclosure is proved not to have been made at the time of entering into the sale agreement.
- Engage experts
Before selling a property with Japanese knotweed, it is advisable that as the seller you seek the services of a reputable company that can help you get rid of the weed plant in such property before proceeding to sell it.
Experts will help you in the professional treatment of the Japanese knotweed such that it will not affect the incoming new owner of the property.
- Fair dealing
Where you know there is an infestation, a fair deal will be to allow a discount on the selling price and let the buyer use the discounted money to treat the property with Japanese knotweed. However, this must receive consent from both parties.
- Conveyance honestly
As the seller of the property, it is always important to ensure that the conveyance process is done as per the legal requirements. You need to ensure that you converse with the seller on any issues that will hamper the deal including the infestation of the property with Japanese knotweed.
Being honest with the other party will simplify the process and enable both parties to arrive at a fair deal that will not jeopardize the needs of the other.
- Alternative means of dispute resolution
Always ensure that the deal is not based on hell-bent terms and conditions as regards the property with Japanese knotweed infestation and its treatment. Always have amicable ways of solving how to get rid of the weed plant at a cost that is affordable.

Want to know more about buying or selling a property with Japanese Knotweed?
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 – hello@knotweedremoval.tips
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