Japanese knotweed
What is RICS management category D for Japanese knotweed?
Category D is “Report”. The RICS journal uses it for knotweed seen off the property, within three metres of the boundary. It says lenders were not expected to retain money, because the owner cannot control the neighbour’s land. Growth further than three metres was not to be given that formal category. Specialist advice is still the journal’s general recommendation when knotweed is reported.
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?
The old approach categorised off-site growth within seven metres. The journal says that distance was reduced to three metres for this category. A surveyor who sees a stand in the next garden should say how they judged the distance and whether they could see it clearly. They cannot walk the neighbour’s garden as of right.
Category D does not mean the neighbour’s knotweed is your problem to excavate. It means it was close enough to report. Your solicitor asks what the seller knows. You ask your lender whether their current rule matches the 2022 expectation. You do not cross the boundary with a spade. If the plant is also on your side of the line, it is no longer only category D.
What should you ask your surveyor?
- Did you see the plant on this side of the boundary, or only beyond it?
- How did you judge the three-metre distance?
- Are you assigning category D, or only noting a plant in the distance?
What are the typical next steps?
- Tell the lender if the report prints category D. Ask them what they need.
- Do not instruct works on the neighbour’s land.
- If you want advice on the risk of spread, ask a remediation specialist and show them the surveyor’s words.
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
What if the plant is four metres beyond the fence?
The journal says growth more than three metres off site was not formally categorised for lenders, though surveyors should keep a site note. Ask this surveyor what they recorded.
Does category D make a mortgage impossible?
The journal said a retention was not expected. Your lender’s current answer is the one that counts. Ask them.