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Autumn is Here- Japanese Knotweed is Receding

Autumn: Knotweed is Dying Off (above ground…)

A long summer has drawn to a close and the temperatures have dropped. We noticed frost in Edinburgh yesterday morning so that spells the end for Japanese knotweed growth in Scotland’s capital as the plant dies back for winter.

Japanese knotweed will remain dormant beneath ground over the winter months but it will still be very much alive. It is best to avoid disturbing the plant’s rhizome structure as you may end up spreading the infestation. Ever wondered what Japanese knotweed rhizome looks like? The pic below shows the woody outer and the bright orange, carrot-like inner.

Japanese Knotweed Rhizome

Japanese Knotweed Rhizome

So what can be done over the winter months in order to eradicate Japanese knotweed?

Excavation & Removal of Japanese Knotweed in Autumn/Winter

Japanese knotweed can be excavated and removed from the ground and disposed of at a licensed landfill site. Screening the soil can be particularly difficult due to high moisture content from rainfall. Another option is to dig it out then bury in a specially constructed cell that will stop it from spreading and it will eventually perish within the cell’s impermeable membrane.

Herbicide Treatment OF JAPANESE KNOTWEED in Autumn/Winter

As far as herbicide application goes, there are products that can be used over the winter, however, finding the ideal conditions for treatment can be problematic.

Often the best plan for management of Japanese knotweed over autumn and winter is to segregate the area and restrict access. Clearly identifying it on a plan of the site as well as erecting warning signage should allow the Japanese knotweed to spend the colder months undisturbed. An eradication programme could start in spring once the weather improves as this will reduce the overall cost of the project.

If you suspect that your site is infested with Japanese knotweed then book a survey to get expert advice and a management plan for tackling this invasive weed. Get in touch here or call 01383 416 556.

IWA. Getting to the root of the problem.