Species guide
Japanese knotweed
Nuisance, not harmfulReynoutria japonica
What does Japanese knotweed look like?
Bamboo-like hollow stems speckled purple, growing in a zigzag, with shovel- or heart-shaped leaves and sprays of creamy-white flowers in late summer.
Is Japanese knotweed dangerous?
Not toxic, but an extremely aggressive invasive that can damage foundations, drains and paving. In some places (e.g. the UK) it's legally controlled and can affect property sales.
What should I do about Japanese knotweed?
Don't dig or strim it — fragments regrow and spreading it can be an offence in some regions. Use specialist removal and check local rules.