How Much Does Japanese Knotweed Herbicide Treatment Cost?

Here at Japanese Knotweed Removal, our herbicide treatments start at £95 (plus VAT) per application. Depending on your requirements, we can either provide a free basic survey and report or a specialist survey and report (which is required by most lenders).

Successful knotweed herbicide treatments can take multiple applications over several years. We typically recommend a three-year treatment programme with a two-year monitoring period. This service starts at £1,395 for an area of up to 25m2 depending on the level of contamination, distance to be travelled and material costs. Insurance-backed guarantees can be added as required.

Prices subject to change. Please call us on 029 2039 7554 to check current prices.

I’ve just had my Japanese knotweed treated with herbicide – now what?

If you’ve just had your Japanese knotweed infestation treated with a herbicide application, you may be wondering what to do next. Here are some dos and don’ts of handling your garden following a knotweed herbicide treatment to ensure success:


  • Read the management plan! If you don't understand anything, reach out and contact us; we will be more than happy to answer any questions you may have
  • Leave the Japanese knotweed alone, and allow the herbicide to work
  • Cut down the dead canes between January & February, allow them to dry out on site
  • Quarantine the area of contamination to prevent traffic spreading the plant material across your property
  • Report any new growth that is outside of the area we are treating


  • Flail or mow Japanese knotweed as this will cause it to spread
  • Spread Japanese knotweed stems and crowns
  • Spread soil contaminated with Japanese knotweed rhizome (any soil that is obtained from ground within 5m of a Japanese knotweed plant could potentially contain rhizome. The rhizome is highly regenerative and will readily grow into new plants)
  • Chip Japanese knotweed material. Mechanical chippers do not kill Japanese knotweed. If you spread chipped material on soil, Japanese knotweed could re-grow
  • Add Japanese knotweed material to compost
  • Cut or trim treated Japanese knotweed plants
  • Attempt to treat the Japanese knotweed yourself with herbicide
  • Disturb the ground within 2-3m of any Japanese knotweed plant
  • Dispose of any knotweed material (including soil from within 5m of any knotweed plant or previously contaminated area) off site
  • Allow access/traffic across the area of contamination
  • Carry out any other action that may result in the spread of Japanese knotweed. If you cause/let Japanese knotweed spread, you could be guilty of an offence under the Wildlife and Countryside Act 1981