Japanese Knotweed

Japanese Knotweed Identification

Identifying Japanese Knotweed

Japanese Knotweed identification is not difficult in the blooming season, which typically lasts from late summer to the middle of autumn. The main features that identify the plant correctly at that time of the year include the size of the plant and the stems. Read on to find out more about how to identify Japanese Knotweed.

Japanese Knotweed

Treatment Options

Japanese Knotweed

Treatment Options

Key Features of Japanese Knotweed

  • 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 a zig-zag shape holding the leaves. Leaves sit alternately 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.

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 on 0161 883 0666 for free advice in the identification of Japanese Knotweed

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