Knotweed do’s and don’ts

To help prevent the spread of this highly invasive plant look at the do’s and don’ts in this section. Causing Japanese Knotweed to spread is illegal so it is important to avoid activities which risk this happening.



  • Do make a plan to eradicate Japanese Knotweed from your site.
  • Do contact  the Environment Agency National Customer Contact Centre for further information on preventing the spread and control of Japanese Knotweed on 0370 850 6506 or their website.
  • Do use herbicides safely and effectively.
  • Do obtain the approval of the Environment Agency prior to treatment if you intend to use a herbicide in or near water on 0370 850 6506.
  • Do follow the manufacturer’s instructions regarding protective clothing and the safe and effective use of herbicides.
  • Do take care to avoid drift, and any damage to non-target plants when applying herbicides. Spraying should be performed during still dry conditions, without rain for 6 hours.
  • Do check qualifications – spraying on land which is not your own should be carried out by an approved contractor with a National Proficiency Tests Council Certificate of Competence.


  • Don’t flail Japanese Knotweed as this could cause it to spread. Cutting with sharp hooks, slashers etc or hand pulling is recommended to avoid any dispersal of cut fragments.
  • Don’t cause the spread of Japanese Knotweed stem and crowns. If you cut down Japanese Knotweed, it is best to dispose of it on site. Material taken off site must be safely contained and disposed of at a licensed disposal site.
  • Don’t try to dig up Japanese Knotweed as this will lead to a significant increase in stem density. Even a tiny fragment of the cut rhizome is capable of regeneration.
  • Don’t spread soil contaminated with Japanese Knotweed rhizome. Any soil that is obtained from ground within 7 m of a Japanese Knotweed plant could contain rhizome. The rhizome is highly regenerative and will readily grow into new plants.
  • Don’t chip Japanese Knotweed material. Mechanical chippers don’t kill Japanese Knotweed. If you spread the chipped material on soil, Japanese Knotweed could regrow.
  • Don’t add Japanese Knotweed to compost. Compost it separately (preferably on plastic sheeting to prevent rooting) so that you can be sure it is dead before you apply it to land.
  • Don’t take Japanese Knotweed to recycling centres that receive garden waste as it will contaminate the compost.
  • Don’t dump garden waste contaminated with Japanese Knotweed in the countryside.
  • Don’t waste time. If Japanese Knotweed appears on your site, treat it immediately. Don’t allow it to become established.
  • Don’t break the law. Remember, if you cause Japanese Knotweed to spread you are guilty of an offence under the Wildlife and Countryside Act, 1981.

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