Japanese knotweed
Dead canes and a contractor's sticker are in the flower bed. Does that sticker prove the knotweed has been eradicated?
No. The sticker does not prove the knotweed has been eradicated. Dead canes and a contractor's sticker show a labelled bed and growth that looks dead. They do not show what is left underground. The survey cannot see rhizomes, cannot audit a treatment programme, and cannot issue a completion certificate because a sticker is in the flower bed. Dead canes can stand while the plant persists below. The sticker records a visit. It does not record eradication.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Treatment programmes for knotweed run over more than one season, and dead top growth is an expected stage, not the end. A sticker may name a firm and a date. It does not show the visits that should still happen, the herbicide record, or a guarantee. The survey can photograph the canes and the sticker. It cannot audit the firm, and it should not convert marketing plastic into a certificate. Eradication is a conclusion the sticker does not contain.
Ask the solicitor for the treatment plan, the guarantee and any monitoring still due, and compare those papers with the bed the survey saw. A lender who asks about knotweed needs those documents, not a sentence that a sticker was spotted. If the papers are missing, the sticker does not fill the gap. Do not tell the seller the survey has signed the treatment off. Dead canes remain dead canes.
What should you ask your surveyor?
- What did the sticker actually say, as far as you could read it?
- Did you see dead canes only, with no view of rhizomes?
- Have you avoided calling the bed eradicated?
What are the typical next steps?
- Treat the sticker as evidence of a contractor's visit only.
- Do not take dead canes as proof of eradication.
- Ask the solicitor for the treatment plan and any guarantee.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
If the canes snap and look brittle, is eradication any closer?
Brittle dead canes show the top growth is dead. They do not show the rhizomes are gone. The survey cannot see below the bed. Fragility of the canes is not a completion certificate, and the sticker still is not one either.
What paperwork would show a programme, rather than a sticker?
A treatment plan, visit records and any guarantee the firm issued. Those are documents for the solicitor to collect. The survey can say a sticker and dead canes were present in the bed. It cannot substitute for the programme papers.