Japanese knotweed and construction sites – herbicide treatment or physical removal?
It’s a question we’re often asked, and there is a very clear answer.
If your planned works are likely to result in ground disturbance do NOT rely on herbicide alone. The entire rhizome system should be removed, because the chances are that not all of the rhizome system will be killed by herbicide, the consequence being that your groundworks will spread the knotweed around the site, and possibly off-site too.