Japanese Knotweed

Fallopia japonica

  1. Wildlife
  2. Wildflowers
  3. Japanese Knotweed


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 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.

Where to find it



When to find it

  • January
  • February
  • March
  • April
  • May
  • June
  • July
  • August
  • September
  • October
  • November
  • December

How can people help

Japanese Knotweed can quickly get a stranglehold in an area, causing problems for our native species. The Wildlife Trusts manage many nature reserves for the benefit of wildlife using various methods to ensure a balance of plants and cover in these fragile habitats. By volunteering for your local Trust you can help too, and you'll make new friends and learn new skills along the way.

Species information

Common name
Japanese Knotweed
Latin name
Fallopia japonica
Height: up to 2m
Conservation status
Introduced species.