Case Study: Japanese Knotweed Control

Flowering Japanese Knotweed (GBNNSS)

Dead stems in the winter shoot in April (GBNNSS)

We frequently provide Japanese Knotweed Management Plans to clients who have an infestation on site.  These are often required by mortgage companies, or as a condition of planning consent.  Implementation is however also crucial, and we have over twenty years experience of treating Japanese Knotweed with herbicide.  Treatment on site is preferable to off-site disposal, but a good treatment programme usually lasts several years, so good planning is essential.

The most common method of treatment is with glyphosate herbicide in September, with an added surfactant.  At this time of year herbicide is readily drawn into the root system, ad the plant dies back for winter.  Spring treatment with trichlopyr is also possible, and combinations can be used in situations where early control s essential.  Treatment can be in situ or on a root barrier membrane in a safe location on site.  Off-site disposal is often prohibitively expensive and should be viewed as a last resort.

Providing an active treatment programme is in place Japanese Knotweed is very rarely a serious structural issue.  Spreading it even accidentally is a criminal offence, so be sure to take the right advice!  Our clients for Japanese Knotweed control include private landowners, Selleck Nicholls Ltd and Wainhomes (Southwest).