Japanese Knotweed Prevention & Removal

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Japanese Knotweed

Japanese Knotweed is a large herbaceous perennial plant which is native to eastern Asia in Japan, China and Korea. In North America and Europe the species has been classified as `invasive' in several countries and has no natural pests or diseases.

Japanese Knotweed has hollow stems with distinct raised `nodes' that give the appearance of Bamboo, though it is not closely related. Stems may reach heights of 3-4m each growing season and has broad oval leaves with small, cream or white flowers which erect 6-15cm long in late summer and early autumn.

The invasive root system and strong growth can damage foundations, buildings, flood defences, roads, paving, retaining walls and architectural sites. It can also reduce the capacity of channels in flood defences to carry water.

In the UK, it is an offence under section 14(2) of the Wildlife and Countryside act 1981 to "plant or otherwise cause to grow in the wild" any plant listed in Schedule nine, Part II to the Act, which includes Japanese Knotweed.

Through comprehensive site surveys to identify the invasive weed and to access the site for any ecological factors or issues that may have an effect on the solution, from here a bespoke solution is provided based on your site conditions, extent of the problem and timescales in the most cost effective manner.

Download the Japanese Knotweed Information Sheet (366kb PDF)


Herbicide & Chemical Treatment-A specially blended treatment designed to reach the high foliage, not ideal if close to water courses and can take 2-3 seasons to be 100% effective.

Stem Injection Treatment-Injected directly into the cane of each plant, this direct targeting ensures the herbicide is received by the crown of the plant and straight into the root system. Stem injection is ideal for sites where spraying or removal isn't an option as it has no impact on surrounding wildlife, trees or vegetation.

On Site Burial-An immediate solution to sites suitable for this treatment, the contaminated material is excavated and buried at least 5m below ground, this must be capped with a clean material.

Sealed Burial-Similar to that of onsite burial but the excavated pit is lined with a geotextile membrane which is fully sealed at all points, the contaminated material is then buried within the membrane which is then sealed together to lock in the knotweed, capped with clean a material. A fast and effective immediate solution and can be easily incorporated into development projects.

Dig & Dump-Simply removing the contaminated areas from site and disposing of them in registered and authorised landfills, a simple process during which care is taken to take as minimal amounts of material away as possible, therefore reducing costs. We conduct the entire process from start to finish and offer alternatives to re-dress the area involved.

Site Relocation-As site conditions can affect treatment, the area can be excavated and the contaminated material can be relocated in a sealed geotextile membrane and taken to another site location for a suitable solution to be applied.

apanese Knotweed is a fast growing invasive plant which requires action. Our solutions follow the Environment Agency codes of practice and are conducted by experienced and qualified specialists. Contact us on 0800 877 6068 to discuss knotweed identification, treatments and solutions.

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