Japanese Knotweed Remediation Strategies

This plant enjoys justifiable notoriety, causing many developers and landowners considerable expense and costly delays to their programme. In its native country of Japan, the plant colonises the slopes of volcanoes. It can grow in the most extreme environments known to man. The plant will force its way through concrete foundations, tarmac roads, between courses of bricks and can grow from 3 metres below finished ground levels.

Japanese knotweed is classed as a Schedule 9 plant under the Wildlife and Countryside Act and therefore it is a classed as a criminal offence to cause this plant to spread either willfully or through neglect. The Environment Agency note that “Identifying Japanese knotweed on a site early lets developers assess and cost options for destroying, disposing of and managing it, as well as negotiating an appropriate change in the purchase price of the land”. The emphasis is therefore on providing total eradication, often as fast as possible but with regard to cost versus programme.

Urban Wilderness firstly offer an identification service, although frequently stands of knotweed are first identified by a preliminary vegetation survey, and secondly we produce Japanese knotweed management plans including eradication proposals, off-site disposal and specialist treatment options and costings. Our management plans clearly identify the landowner’s statutory obligations and define the contractor's responsibilities. We can then brief and manage the eradication process and ensure that the works are guaranteed by a qualified eradication specialist.   

The eradication, safe disposal and remaining on-site management issues (such as quarantining or bunding) of Japanese knotweed are often then incorporated into a site-wide pre-construction health and safety file. Land contamination issues are highlighted from the outset, preventing the spread of the plant whilst operating in accordance with current statutory guidelines.

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