Japanese knotweed

Japanese Knotweed

©Philip Precey

Japanese knotweed

Scientific name: Fallopia japonica
Introduced from Japan in the 19th century, Japanese knotweed is now an invasive non-native plant of many riverbanks, waste grounds and roadside verges, where it prevents native species from growing.

Species information


Height: up to 2m

Conservation status

Invasive, non-native species.

When to see

January to December


Japanese knotweed was introduced to the UK from Japan in the 19th century as a garden plant, but has since become established in the wild, rampaging across roadside verges, riverbanks and waste ground. It is a fast-growing, invasive weed, which prevents other native species from growing, and is often used to highlight the issues of introducing alien species. Many organisations, including Wildlife Trusts, are committed to the removal of this invasive plant in order to allow our native wildlife to thrive.

How to identify

Japanese knotweed is a very tall plant with large triangular leaves, hollow, red stems that are a bit like bamboo, and small, white, tufty flowers that appear in late summer and autumn.



Did you know?

Japanese knotweed is also known as 'Monkeyweed', 'Elephant Ears' and 'Donkey Rhubarb'.

How people can help

The Wildlife Trusts work with pest controllers and organisations dealing with alien species to find the most wildlife-friendly solutions to some of our everyday problems.