Japanese Knotweed

Japanese Knotweed

Japanese Knotweed (Fallopia Japonica) is an attractive but rapidly, fast growing plant.

Under no circumstances should Japanese Knotweed be disposed of in your green garden or blue recycling bins. Please use a specialist contractor.

In winter the plant goes beneath the ground but by early summer the bamboo-like stems shoot to over 2.1m (7ft). Removing the plant is very difficult whether it's through hand or chemicals. The plant suppresses all other growth and can affect both wall and building foundations.

While the plant is not illegal new legislation around Japanese Knotweed was introduced by the Government.

The problem with Japanese knotweed

Japanese knotweed is not unattractive but its rapid, strong-growing annual growth and relentless speed allows it to easily overwhelm other garden plants. The plant does not produce seeds, it sprouts from very small sections of rhizomes. The plant can disrupt walls, pavements and foundations. Under the Wildlife and Countryside Act 1981 it is an offence to cause Japanese knotweed to grow in the wild.

New legislation

An amendment to the Anti-Social Behaviour, Crime and Policing Act 2014 includes a section on Japanese knotweed and other invasive non-native plants including the Himalayan balsam and Giant hogweed. The legislation identifies:

  • On your property you should aim to control these plants and prevent them from becoming a problem in your area. If they have a 'detrimental effect of a persistent or continuing nature on the quality of life of those in the locality', the legislation could be used to enforce its control.
  • Control can be carried out by the homeowner and doesn't require a specialist company. However, a specialist company will be skilled at control and can dispose of the plant waste.
  • Identification is important. Japanese knotweed can sometimes be confused with other plants including the Persicaria micrcephala 'Red Dragon', Leycestria Formosa and Houttuynia cordata (see below images).
  • Where problems with Japanese knotweed occur in neighbouring gardens, we suggest that you speak or correspond directly with your neighbours (who may already be taking action to control this difficult weed). These informal steps should be taken before contacting the council.

How to control Japanese knotweed

All weeds can be controlled without weed killer, but Japanese knotweed is persistent and deep rooted which is very difficult to eradicate.

  • Digging: Due to the depth, regrowth usually occurs. This method also causes disposal problems. Under the Environmental Protection Act 1990 disposal can only take place at licensed landfill sites. Specialist Japanese knotweed contractors are licensed to safely remove the weed.
  • If digging out is attempted, remove as much root as possible, then repeatedly destroy re growth. This process may take several seasons.


  • Most effective and simplest method is when Glyphosate is applied to the foliage which is then passed to the underground parts. The best time for spraying is around May when the weed is 90cm (3ft) and then a reapplication in late summer.
  • Glyphosate-treated knotweed will often produce small-leaved bushy re growth the following spring. This is very different in appearance to the normal plant and is essential that the re growth is treated immediately.

Other forms of Glyphosate include Scotts Roundup Ultra 3000, Scotts Tumblewood, Bayer Tough Rootkill or Doff Maxi Strength Glyphosate Weedkiller.