Japanese knotweed
Knotweed is in the neighbour's hedge and not in your beds. What has the survey not been able to say about rhizomes under the fence?
The survey has not been able to say whether rhizomes run under the fence. The knotweed that was seen is in the neighbour's hedge, not in your beds, so the stems in view are on the neighbour's side. Rhizomes are the underground stems by which the plant spreads, and they are not visible from the hedge. The survey has recorded plants in that hedge and none in the beds. It has not dug, has not mapped roots, and has not decided that the fence stops the plant. GOV.UK guidance is about stopping knotweed from spreading.
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?
Japanese knotweed spreads from a rhizome network that can sit beyond the stems you see. A hedge on the neighbour's side can be the visible part, while the rhizome is on either side of the boundary or on neither. Absence from your beds is an above-ground finding about those beds. It is not a survey of the soil under the fence. The home survey does not excavate. It cannot draw a line under ground it did not open and call that line the end of the plant.
Tell the solicitor that knotweed was seen in the neighbour's hedge and not in the beds, and that rhizomes under the fence were not determined. Ask what the seller and the neighbour have already been told, and whether a management plan exists. GOV.UK explains that knotweed should not be caused to spread. The home survey has not written a management plan and has not cleared the boundary. A specialist can be asked about the rhizome. That request is not this report.
What should you ask your surveyor?
- Where was knotweed seen, and where was it absent?
- Have you left rhizomes under the fence unstated?
- Did you record an above-ground limit rather than a clearance of the soil?
What are the typical next steps?
- State that rhizomes under the fence were not determined.
- Tell the solicitor about the knotweed in the neighbour's hedge.
- Do not treat clear beds as a clear boundary.
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 beds are mulched and tidy, are they free of knotweed?
Tidy mulch shows the surface. The survey did not see knotweed in the beds and has not said rhizomes are absent under them or under the fence. Mulch can hide young growth. The finding is what was visible in the hedge, not a clearance of the soil. A specialist would have to go further than this visit.
Can the survey require the neighbour to remove the hedge?
No. The survey records plants it could see. It does not instruct a neighbour, and it does not give anyone power to remove a hedge. GOV.UK guidance is about not causing the plant to spread. What the neighbour must do is for the parties and their advisers. The rhizome question under the fence stays unanswered here.