Japanese knotweed can grow vigorously and damage buildings and hard surfaces. Once established it can be particularly hard to control.
The Environmental Health Section often receives enquiries with regards to Japanese knotweed and although it causes problems, it causes no threat to public health. Managing knotweed is the responsibility of the owner/occupier the property.
You are not legally obliged to remove or control Japanese knotweed in your garden, however if you allow knotweed to grow onto other people’s property, you could be prosecuted.
It is an offence to plant or cause Japanese knotweed to spread in the wild under The Wildlife and Countryside Act 1981 and all waste containing Japanese knotweed comes under The Control of Part II of the Environmental Protection Act 1990.
The disposal of Japanese knotweed is not straightforward. It cannot be disposed of via the garden waste bins. It must be treated as controlled waste and waste transfer documentation is needed. Only licensed landfill sites can accept it.
Natural Resources Wales has an useful webpage which contains information on how to prevent the spread and manage knotweed problem as well as disposing of it correctly.
The guide is aimed towards developers; however the information contained is useful.
Other links that may be useful are listed below.