Giant Knotweed

infestation of giant knotweed on waste ground

What is Giant Knotweed?

Giant knotweed (Fallopia Sachalinensis) is a striking and very large plant forming stands of largely un-branched stems, bearing leaves up to 3 times larger than those of Japanese Knotweed. These are reminiscent of the foliage of the broad-leaved dock, (Rumex Obtusifolius). The flowering of both male and female plants starts later than Japanese knotweed, and flowering is less prolific.

This plant is native to the island of Sakhalin to the north of Japan, and the remote island of Ullung-do between Japan and Korea.

Knotweed removal solutions

The vast knowledge and many years experience the TCM team possess enables us to provide the most effective and efficient Knotweed removal solutions for both commercial and residential landowners.  If you are concerned about the presence of Giant Knotweed at your location, please contact TCM to arrange for a site visit, and to discuss your treatment options.

Why is Giant Knotweed a problem in the UK and Ireland?

Giant knotweed spreads by the extension of the rhizome system and is mainly dispersed by the transport of portions of rhizome to fresh sites. However, it has not shown the destructive competitiveness of Japanese Knotweed.

The role of true Giant knotweed seedlings in the spread of the plants in the UK has received little discussion, though it is likely to be insignificant. Substantial genetic diversity in the plants has been noted, though this is likely to have arisen through multiple introductions of the species from various parts of the native range, rather than through home-produced seedlings.

Giant knotweed’s true significance is as the main pollen parent of the hybrid, Fallopia X Bohemica, whose hybrid vigour may render it the greatest threat, so far, of all.

Giant Knotweed and the Law

  • Wildlife and Countryside Act (1981)

  • Environmental Protection Act (1990)

  • Anti-Social Behaviour, Crime and Policing Act (2014)


What does Giant Knotweed look like?  View our image gallery to help you identify Giant Knotweed on your land.


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TCM supply eradication solutions for homeowner. If you have Japanese Knotweed on your land, or your buyer’s mortgage has been refused - we can help. Contact us today.



TCM deliver science based knotweed removal solutions to a wide range of industries and organisations including construction, rail, road, the London Overground, property developers, local councils and more.

Howard Downer


Howard Downer, AKA Dr. Knotweed, has over 20 years of experience as an Environmental Consultant and is regarded by his peers as one of the most knowledgeable people in the Japanese knotweed industry.

Follow Dr. Knotweed to hear about the latest developments regarding Japanese knotweed and the implications of infestation.

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