Japanese Knotweed

┬ęPhilip Precey

Japanese knotweed

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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.

Top facts


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.

What to look for

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.

Where to find


Did you know?

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