Selling a home with Japanese knotweed

Knotweed on or near your home doesn’t stop you selling it. What it does mean is a few extra questions from the buyer’s side, and the answers go much more smoothly if you’ve got your paperwork ready.

If you’re new to knotweed, our Japanese knotweed overview covers the basics.

What you may be asked

When you sell, you’ll fill in forms about the property for your buyer. There may well be a question about knotweed. In England and Wales the form is usually the Law Society’s TA6 Property Information Form. The current 6th edition, which replaced earlier editions for new sales from 30 March 2026, asks “Is the property affected by Japanese knotweed?” with the answers Yes, No or Not known. If you answer yes, it asks whether a management and treatment plan is in place and for a copy of the plan with any insurance linked to it. It also asks whether a knotweed survey has been carried out. The Law Society’s notes say a property is usually considered at risk if knotweed is growing on it or within 3 metres of its boundary, and that because roots can be hidden underground, many sellers answer “Not known”. You must answer truthfully, completely and as accurately as you can from your own knowledge, and say so if you don’t know. Buyers can rely on your answers. The Law Society’s notes say that if you give misleading information, the buyer may be able to claim compensation after completion. If anything changes before the sale, tell your conveyancer straight away.

The safest approach is to answer plainly and back it up with documents. If you’re not sure of the answer, tell your conveyancer (the solicitor or licensed conveyancer handling the legal side of your sale) before you fill in that part of the form.

What a buyer’s lender may want

If your buyer needs a mortgage, their lender’s view matters to your sale too. The buyer’s lender will rely on its valuer, who assesses knotweed using a framework set by RICS, the surveyors’ professional body. Since 2022 it has used four management categories instead of the old “7-metre rule”. Categories A and B mean the plant is damaging a structure or is likely to restrict use of outside space such as the garden, paths or driveway. For these, RICS expects most lenders to want an inspection by a specialist from a recognised trade body and a management plan with an insurance-backed guarantee, often holding back part of the loan until that’s in place. Category C is lower impact and shouldn’t need any work as a condition of the mortgage. Category D usually means it’s on neighbouring land within 3 metres of the boundary, which is reported but only rarely made a condition. Each lender still sets its own policy.

You can’t control what a lender decides. But you can make it easy for them to say yes by having the right documents ready before a buyer’s surveyor finds the plant. Our guide to buying a house with Japanese knotweed covers what your buyer and their lender are likely to ask for.

What helps

One document that can help is a management plan. That’s a written plan from a specialist setting out what treatment will be done, over what period and how progress will be checked. RICS says a plan should include a record of the infestation, a scaled plan with photos, details of the firm and its methods, a treatment schedule kept up to date as work is done and, at the end, a certificate confirming the work is complete after a two-year “no growth” period. Treatment with weedkiller needs at least four years of treatment and monitoring before that certificate can be issued. RICS also says the plan should cover the whole property, be transferable to future owners and come with an insurance-backed guarantee. That’s a guarantee from the treatment firm to come back and re-treat any regrowth, usually for at least five years after the work is finished, with a separate insurance policy that keeps it valid if the firm stops trading. Check the guarantee’s own terms to see what’s needed to pass it to your buyer.

If you’ve already had treatment, a tidy file showing what was done and when is often half the job. Paperwork is rarely anyone’s favourite part of selling a house, but here it does real work.

When to get help

You can gather records, take photos and talk to your neighbour yourself. Bring in a specialist when you need something written that a buyer or lender will rely on: a survey confirming what’s there, or a management plan for dealing with it. Our guide to getting a knotweed survey covers how to choose a specialist.

It also helps to tell your estate agent and conveyancer early, so nobody is caught short halfway through the sale. Agents do have their own duty. Under consumer protection law they mustn’t leave material information out of a property listing, and National Trading Standards says any information can count as material if it would affect a buyer’s decision. That law is now in the Digital Markets, Competition and Consumers Act 2024, which replaced the older Consumer Protection from Unfair Trading Regulations 2008.