Japanese Knotweed Identification

Key Features of Japanese Knotweed

Japanese Knotweed identification is not difficult in the blooming season, that typically lasts from late summer to the middle of autumn. The main features that identify the plant correctly at this time of the year include the following:

Japanese Knotweed key features

  • The plant’s size, typically 2-3 m (6-10 ft) tall.
  • Distinct upright, semi-woody, hollow stems with nodes like bamboo, with a diameter up to 4 cm (1.6 in). The stems are pale-green, often with red or purple speckles in late spring to mid-autumn.
  • Hollow branches of zig-zag shape holding the leaves. Leaves sit alternatively on the opposite sides of the branch.
  • Leaves and side shoots grow from nodes.
  • Leaves are heart-shaped, with flat bases, up to 10-15 cm (3.9-5.8 in) long.
  • Flowers are creamy-white coloured and are arranged in clusters of 8-12 cm (3.2-4.7 in) long.

You can download a Japanese Knotweed fact sheet (106 kB) or ID sheet (4.5 MB) from the official website of GB Non-Native Species Secretariat for more information about Japanese Knotweed.

Still not sure if Japanese Knotweed is present on your land or neighbouring area?

Photo Gallery

Look at our high-quality photographs that will help you identify Japanese Knotweed.

Free Japanese Knotweed Identification

Our team is trained to a very high standard in Japanese Knotweed identification at any time of year. Please send us photos of suspicious plants you are concerned with using our Enquiry Form on our contact page. If possible, our specialists will identify Japanese Knotweed from your photographs for FREE. However, pictures do not always provide a complete guarantee of the presence of knotweed. If we can not identify the plant using your photos, please book a survey of your site.

Call us for free advice in the identification of Japanese Knotweed

0161 883 0666