Japanese knotweed is an invasive, non-native plant that was introduced to the UK in 1825. It grows and spreads extremely quickly. This means it can overwhelm other plants and destabilise building structures.
Japanese knotweed can grow in any type of soil, no matter how poor. It can grow up to 20 centimetres a day in spring or summer. It doesn’t produce seeds, but spreads through an underground root-like stem (rhizome) and cut stems.