It is considered an offenceto cause Japanese knotweed to be spread from one site to another. If theinvasive knotweed is found on a site boundary, crossing into adjoiningproperties, then it is often the case that the origin of the Japanese knotweedis unknown and that responsibility for the may beshared.

In the Wildlife andCountryside Act 1981, knotweed is listed in , Section 14. Itis an offence to actively plant or otherwise cause the species to grow in thewild. But it is not actually illegal to have it on your land, nor is there anyspecific law against allowing it to spread, although doing so could be anuisance.

In the EnvironmentalProtection Act 1990, Japanese knotweed is classed as ?controlled waste? andmust be disposed of safely at a licensed facility according to theEnvironmental Protection Act (Duty of Care) Regulations 1991. Soil containingthe rhizomes of the plant can be regarded as contaminated and, if taken off asite, must be disposed of at a suitably licensed facility. At landfill sites,the waste due to Japanese knotweed removal must be buried to a depth of atleast 5 meters.

If the area of infestation inquestion is not to be disturbed or built upon at any time in the near future,then the Japanese knotweed can often be treated with a specific herbicide thatwill be part of a strategy.

This will involve thespraying of the invasive plant with herbicide for several years, until therehas been no re-growth for at least two years. It is important to remember thatin the United Kingdomspraying of Japanese knotweed carried out near water, requires the permissionof the Environment Agency; this is obtained with form WQM1. Japanese knotweedherbicide spraying near or in water will require the use of a non persistentherbicide such as glyphosate. This type of herbicide will break down quickly incontact with the soil, microbes and water. If no watercourses or groundwaterare nearby, then it may be possible to use a more persistent herbicide such asTordon 22k (picloram) in order to treat the Japanese knotweed growth.

Japanese knotweed hinderingconstruction works or obstructing water-ways can be treated through excavation.Excavation of Japanese knotweed is more costly than the control of Japaneseknotweed through herbicide use, but the use of excavation to control the spreadof Japanese knotweed is a more immediate solution to the problems posed byJapanese knotweed.