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Commercial Eradication Solutions


  • What is Japanese knotweed?

    Japanese Knotweed is a non-native deciduous invasive plant – for a full description please click here.

  • What does Japanese knotweed look like?

    Our Japanese Knotweed page will take you to our seasonal identification gallery of Japanese Knotweed, you can find that here. If you require further help with identification, please send us an image of the plant in question and our experts will check to see if it is indeed Japanese Knotweed. Send your image here.

  • Is Japanese knotweed poisonous?

    No, Japanese Knotweed is not poisonous and some cultures eat parts of the plant, however we do not recommend doing so.

  • How does Japanese knotweed spread?

    Japanese Knotweed is spread by man. The seeds it produces are not viable, so each new infestation has originated from a tiny part of the plant that has been scattered from the main plant – cutting, flailing, incorrect and illegal disposal of any parts of the plant – it is an extremely invasive plant and it is all too easy to allow the plant to spread.

  • I have Japanese knotweed on my land – can I mow it?

    No, do not mow it. You will create tiny off cuts that can spread and grow again. Similarly, do not compost Japanese Knotweed or try to burn the plant – you will not be sure of eradication, and should you ever wish to sell any buyer will struggle to obtain mortgage funding.

  • Can I kill Japanese knotweed myself?

    Here at TCM, we say no. Always ask the experts.

    A piece of rhizome the size of your fingernail is capable of regrowth and a license is needed to take Japanese Knotweed to a landfill (it is also illegal to put it in a garden waste or compost bin).

  • How can you kill Japanese knotweed?

    This is done either with herbicide or through a dig out method, both of which are applicable to commercial and residential customers. The decision between the two will come down to timescale, access to the infestation and budget.

    At TCM, we cover both options with our A+ Lloyds backed Insurance Backed Guarantee (IBG).

  • What should I do if my neighbour has Japanese knotweed close to my boundary?

    If appropriate, approach your neighbour and ask if they realise that the shrub at the edge of their garden is indeed Japanese Knotweed. It is not illegal for them to have the plant on their land, but it would be illegal for it to be allowed to grow or spread onto your land and the best way in these situations is always to find an amicable way forward with the help of a recognised professional eradication firm.

  • What guarantees do TCM offer?

    We provide a Lloyds backed A+ Insurance Backed Guarantees (IBG) which ensures the guaranteed obligation is met even if TCM should no longer be trading. This then gives full peace of mind that should remedial works be required, a fully independent fund will be available.

  • How long does it take to eradicate Japanese knotweed?

    This will be dependent on the size and age of the infestation, the access required to treat the infestation and the time scale available. The average infestation in an average family garden, with easy access would be £2,000.

  • Can Japanese knotweed grow through concrete, tarmac and foundations?

    Japanese Knotweed cannot grow through concrete, but it CAN grow through any cracks or weak points within that concrete.

    Japanese Knotweed can grow through tarmac, brickwork and pipes, particularly if they are in poor condition. It will search for cracks in the structure and force its way through, making the crack worse. It shoots up easily between paving slabs and decking areas in a garden.

  • Is it illegal to have Japanese knotweed on your land?

    It is not illegal to have Japanese Knotweed on your land, however it is illegal to allow it to spread across your boundary to an neighbouring property and can leave you open to a legal challenge. For more information on Japanese Knotweed and the law, please click here.

  • What geographical areas do TCM cover?

    TCM works in all parts of the UK and the Republic of Ireland. In recent years the largest levels of infestation have been found in London, the South East, Wales and Ireland.

Got a question for us?


Howard Downer, MD of TCM Ltd


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 of about the latest developments regarding Japanese knotweed and the implications of infestation.

Latest Residential Case Studies

  • Japanese knotweed growing in front garden of a London home

    Japanese knotweed – London

    Japanese knotweed was growing in the front garden of a North London property. The homeowner wanted to sell in 2017…

  • Image of a Japanese knotweed survey being undertaken

    Homeowner Wishing To Sell

    Has your mortgage been refused? TCM helped a homeowner who was wishing to sell his property but had Japanese knotweed…

Latest Commercial Case Studies

  • Japanese knotweed Soil Screening Project in Dorset

    Soil Screening Project, Dorset

    TCM soil screening project – eradicating Japanese knotweed at the site of commercial home building project Devon, UK.

  • Japanese knotweed soil screening on commercial site in Wales

    Brownfield Site, Glasgow

    Commercial soil screening project. TCM were commissioned by a Commercial company wishing to develop a brownfield site in Glasgow, Scotland.…

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