Here’s What to do when selling a London home with Japanese knotweed

What should you do when selling a home with Japanese knotweed?

The mere presence of Japanese Knotweed at, or even near, your home, could make your property difficult to sell. So what should you do if you think you have knotweed and you want to sell your home?

The TA6 Property Information Form

If there is knotweed at your property, failure to disclose its’ existence to a buyer can have legal consequences.


At the start of the conveyancing process, you will need to fill in various forms including the TA6 Property Information Form. Once completed, this legal document is forwarded to the buyer’s solicitor as part of the pre-contract paperwork.


The form asks if the property is “affected by Japanese Knotweed”. For a legally binding document, the word ‘affected’ may seem imprecise. As a layman, you might well consider a plant at the bottom of the garden to have little effect on your home.


The Law Society’s guidance notes, updated in 2020, adds clarity urging disclosure if knotweed is “present in the ground or within 3 metres of the property boundary”.

So how should I answer the question?

In short, honestly. Failure to disclose the presence of knotweed, as with any other property defect referred to on the TA6, could result in the new owner taking legal action on the basis of misrepresentation.


The new owner could seek to recover their losses, including any loss of value in their property (typically up to 10%) and their legal costs.


In answering the question, you must select one of three options:


As a seller, you will naturally want to present your property in the best light. As such, you may be inclined to tick ‘No’ if you are not aware of any knotweed on your property.


However, the Law Society states that you should answer ‘No’ only if you are:


certain that no rhizome (root) is present in the ground of the property, or within 3 meters of the property boundary even if there are no visible signs above ground.”


This is a very difficult condition to meet with absolute certainty. Even if there is no visible growth, the subterranean rhizome system can be dormant for extended periods. It may be, for example, that a previous owner self-treated or cut back the knotweed. Unless you plan to excavate your garden (and your neighbors), you cannot be certain there are no hidden rhizomes.


Your conveyancing solicitor will, therefore, advise against selecting ‘no’.

‘Not known’

Unless knotweed has been positively identified, you should answer ‘Not known’. This puts the onus on the buyer to carry out their own due diligence, as they would for any other property defect. If there are any visible signs of knotweed on the property it should be picked up by home surveyor. Buyers can also commission a specific knotweed survey if they wish.


Chris Salmon, Director of Conveyancing Panel Quittance Legal Services, said “Sellers may be reluctant to answer ‘Not known’. They may have lived at the property for years and feel confident that there is no evidence of knotweed. Answering ‘Not known’ feels evasive – leading the buyer to infer the worst.”


“However, since the Law Society updated its TA6 guidance notes in February 2020, it is now standard practice for sellers to answer ‘Not known’. Answering ‘No’ could now seem more dubious to a buyer’s solicitor.”


If knotweed is present on or within 3 meters of your property’s boundary you must answer ‘Yes’. You will then be asked if there is a treatment plan in place and, if so, to supply a copy.

What should I do if I intend to sell a property that is affected by knotweed?

If you suspect the presence of knotweed, you should get it confirmed by a professional as soon as possible. If you bury your head, the knotweed will most likely be picked up by the buyer’s surveyor. At best this will delay the sale. At worst it could render your home unmortgageable.


Lending criteria vary from lender to lender and the situation is constantly evolving. You can check a lender’s current lending criteria in the UK Finance Mortgage Lenders’ Handbook.


At the point of writing, many lenders require a knotweed treatment plan if there is knotweed on or within 7 meters of the property. The plan must be in place with a qualified person or company, such as an accredited member of an industry-recognized trade association.


The plan should be underwritten by a 10-year insurance-backed guarantee (IBG). An IBG ensures that knotweed treatments will continue if the contracted company goes bust.


Without a plan in place, you may find that your property is unmortgageable and its value consequently reduced.


Before you put your home on the market, you should contact an accredited knotweed treatment company to carry out a survey. If knotweed is confirmed, you should take out a plan. Lenders will usually require the full plan to be paid for upfront.


If the above is carried out before you put your property on the market, you can disclose the presence of knotweed with minimal concern that it could jeopardize your sale.