Think You’ve Spotted Japanese Knotweed? Here’s What to Do Next

If you suspect Japanese knotweed is on the plot—or even nearby—it’s important to act fast. Lenders, valuers, and buyers treat it as a serious risk to both the structure and value of a property. Even if it’s just a suspicion raised by the valuer during a mortgage valuation, a formal survey is the next step.

You’ll need to instruct a qualified firm that specialises in Japanese knotweed surveys. Make sure they’re members of the Property Care Association (PCA) - this is essential, as most mortgage lenders and insurers will only accept reports and treatment plans from PCA-registered professionals.

The survey will provide a formal Japanese knotweed identification report, mapping the exact location of the plant. It will show whether knotweed is on the property, adjacent to it, or near the boundary. The report will also assess how severe the infestation is and recommend any remedial work or treatment required—such as herbicide application or excavation.

Some firms offer initial surveys for free, but be aware that a fee might be charged if no evidence of knotweed is found. Always check this in advance to avoid surprises.