Japanese knotweed

Japanese knotweed is a herbaceous plant originating from Asia. It was first noted in the 1900 in London, it has since spread rapidly throughout Britain.

Further information

The problem with Japanese knotweed

Japanese knotweed is an invasive species resistant to common methods of control. It damages wildlife habitats wherever it appears and causes many practical problems, including damage to structures

What does it look like?

Every spring the plant produces new shoots that grow into thick green stems often clumped together to form bushes. Its leaves are shield shaped with a flat base, often emerging from the stem in a zigzag pattern. The stems are hollow with regular nodes and can look similar to bamboo. During spring/summer they are green with purple speckles and grow in clumps.

Knotweed flowers at the end of summer and produces clusters of tiny white/cream flowers. Every winter the plant appears to be dead because the shoots die back, leaving a group of dry canes. Throughout the year the roots stay alive. These roots are brown on the outside with white shoots and bright orange inside.

Control and disposal

Legislation forbids allowing Japanese knotweed to spread into the wild. It is also illegal to move it from where it is growing unless this is carried out by a licensed operator. Legislation is also in place to control the nuisance caused to occupiers affected by Japanese knotweed growing on adjoining land.