At SE Knotweed, detection dogs are trained to scent dormant knotweed rhizome below ground, which can confirm the extent of a stand a visual survey alone would miss on a development or boundary site.
A detection dog survey costs from around £500 upward depending on the site and travel, more than a standard visual survey, so it is used where confirming below-ground extent justifies the fee.
At SE Knotweed, Japanese knotweed detection dogs are dogs trained to scent the plant's rhizome below ground, so they can locate dormant or hidden growth that a visual survey would miss. A dog indicates where it detects the scent, and a surveyor then confirms and records the find, so the dog is a tool within the survey rather than a substitute for it.
They are most useful where the below-ground extent matters and cannot be seen: after visible canes have been cleared, on a development plot, or in a boundary dispute. For a visible garden stand a trained surveyor is enough, so we advise on when a dog genuinely adds value.
Detection dogs find dormant rhizome by scent, picking up the odour of live knotweed root even when there is no growth above ground and the canes have died back for winter. A handler works the dog across the site in a pattern, and the dog gives a trained indication at the point of the scent, which the surveyor marks and investigates.
This matters because the rhizome can extend well beyond the visible canes and stays alive underground through winter, when a visual survey is hardest. The dog narrows down where to dig a trial pit to confirm the extent, rather than guessing across the whole plot.
A detection dog survey adds value where confirming the below-ground extent is critical: a development plot where the footprint must be clear, a boundary dispute where the source and spread are contested, or a property bought after visible growth was cleared and the buyer needs certainty. In those cases the fee is justified by the risk it resolves.
For a routine garden stand with visible canes, a standard survey is enough and a dog is rarely worth the cost. We are honest about that, because the point is to spend the survey budget where it answers a real question rather than adding a service for its own sake.
A detection dog survey costs from around £500 upward depending on the site size, access and travel, which is more than a standard visual survey at £150 to £500. The premium reflects the specialist handler and dog team and the time to work a site methodically.
It is used where confirming below-ground extent justifies the fee, such as a development or a disputed boundary, rather than as a default. We give a figure once we know the site, and we will tell you honestly whether a standard survey would answer your question for less.
Knotweed detection dogs are reliable at scenting live rhizome when the dog is properly trained and the ground conditions allow the scent to reach the surface, but they are a survey aid rather than an infallible test, so a surveyor confirms every indication before it is recorded. Very deep rhizome, hard capping or heavy contamination from other sources can reduce what a dog picks up.
Because of that, we treat a dog's indication as a prompt to investigate, usually with a trial pit, not as a final answer on its own. Used that way alongside a standard survey, the dog adds real value on the sites that need it, which is why we advise on when it genuinely helps rather than offering it as a default.
A detection dog survey supports a claim by evidencing where live rhizome runs below ground, which helps establish the true extent of an encroachment and whether it crossed a boundary. Combined with the surveyor's record and any trial pits, it strengthens the technical evidence a private nuisance claim relies on.
Where a claim proceeds, that evidence feeds a CPR Part 35 expert witness report. The dog does not decide the legal case, which turns on breach of a duty and on the law, but it can settle a factual dispute about how far the plant has spread.
Tell us the address and what a surveyor flagged. We confirm the plant, record the RICS category and set out the figures.