Japanese Knotweed Removal On Commercial Sites [Infographic]

27th April, 2017

Why is Japanese knotweed considered so problematic once identified on a commercial site?

  1. Fallopia japonica infestations on development sites can cause major delays, additional costs or cancellations of entire projects.
  2. Knotweed roots can remain dormant in soil for years, making it a big surprise once knotweed re-emerges in a previously contaminated area.
  3. Knotweed infestation must be completely removed before the planning permission is granted.
  4. Knotweed is removed from building sites mechanically or treated by chemicals.

How is knotweed removed from building sites?

Methods of Japanese knotweed eradication on commercial sites that have been proven successful include the following:


Mechanical removal of knotweed plants and contaminated soil. Most effective when soil needs to be removed anyway, to make room for foundations. Quicker than chemical treatment.


Excavated knotweed plants and soil can be buried on-site or disposed of at a controlled waste facility. Knotweed must be encapsulated in a membrane and buried at least 2 m beneath the ground level.

Herbicide treatments

Knotweed herbicide treatments take 3-5 years. Herbicides can be applied either by foliage spraying or direct stem injections into plant’s rhizomes. Considered more environmentally friendly, stem injections do cause collateral damage, hurting nearby native vegetation.

Before booking a treatment plan…

Make sure your PCA-approved contractor adheres to:

  • “Duty of Care” – Environmental Protection Act (EPA) 1990
  • Japanese Knotweed Code of Practice by The Environment Agency (recent update: 2016)
  • Wildlife and Countryside Act 1981

Infographic created by Japanese Knotweed Specialists – a PCA-accredited Japanese knotweed removal company providing effective solutions for eradication of invasive weeds on commercial sites across the UK. To consult your options for a bespoke knotweed management plan and eradication, or book your knotweed survey, contact our experts at 0800 122 3326.

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