Japanese knotweed
You already have a mortgage offer, and knotweed is in the survey. Why must the lender still be told, rather than hoping the offer has closed the point?
Because knotweed is in the survey, the lender must still be told, and the mortgage offer already out has not closed the point. An offer was made on what the lender knew then. The survey's report of knotweed is later information. Hoping the offer has swallowed it leaves the lender in the dark. GOV.UK's guidance is about not spreading knotweed. It is not a reason to keep the survey quiet. Tell the lender. Do not invent a treatment distance while you do it.
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?
Offers feel final because the letter looks final. They are still the lender's offer, on the lender's conditions. A home survey that reports knotweed is exactly the sort of fact borrowers are expected to pass on, not to file until completion. RICS knotweed material is about the plant being a property issue. It does not say an issued offer ends the conversation. The surveyor has not told the lender for you. You, through your adviser, still have to.
Send the survey wording, not a softened paraphrase, and say where on the plot the surveyor reported the plant. Do not add metres of 'safe distance' the report did not measure. Do not dig it out over the weekend, which risks spreading it, the thing GOV.UK tells people not to do. If the lender asks for a specialist, that request is new work. The existing offer has not closed it, and silence is not a way of closing it either.
What should you ask your surveyor?
- Where does the survey say the knotweed was seen?
- Is that wording what the lender should receive, without a distance you added?
- Does the existing offer, in your view, leave this point open?
What are the typical next steps?
- Tell the lender the survey reports knotweed.
- Do not hope the offer already out has closed the point.
- Do not dig the plant out, and do not invent a treatment distance.
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 offer is unconditional, can you stay quiet?
No. Quiet is not a closure. The lender still has to be told that the survey reports knotweed. The offer has not ended that point.
Does a management plan in a drawer replace telling them?
No. A plan in a drawer is not the survey. The lender still needs the survey's knotweed report, and the offer has not closed it.