Study reveals best Japanese knotweed treatment methods


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A recent study undertaken by academics at the University of Liege has shown the effects that different chemicals have on Japanese knotweed. The study was conducted over two years and looked at the volume, height and density reduction when chemicals were sprayed or injected to control the invasion of Japanese knotweed.

Japanese knotweed treatment methods

The study had some fascinating results, although no chemicals were shown to completely eradicate the Japanese knotweed with a single treatment.  New methods of controlling Japanese knotweed were also trialled that were non-chemical methods and involved cutting the Japanese knotweed. The results of the interventions were taken after a one year and then a two-year period, allowing the study to assess if the control methods are effective in controlling Japanese knotweed.

The most effective method of Japanese knotweed treatment was using a glyphosate-based herbicide chemical (similar to the control treatments used at Wise Knotweed Solutions) that was injected into the stem of the plant.  The research advised no new shoots of the plant were found after the first year however, stunted shoots were discovered within year 2 that highlighted the need of a regular control injections of a set period of time to ensure the weed was eradicated. 

Of the none chemical treatment methods, repeated monthly cuttings from July to October followed by the plantation of willow cuttings and then more monthly cuttings from May to October for two years was the most effective at reducing and controlling the development of Japanese knotweed.

Findings of Japanese Knotweed treatment study

The overall findings of the report were that the methods used could help to curb the invasion of Japanese knotweed but would be unlikely to completely eradicate the problem without a controlled treatment program over a set period of time. The report concluded that the most successful methods should be used as a control strategy and that prevention along with a public awareness campaign, so the public can identify Japanese knotweed, should be used to combat the invasion of Japanese knotweed.

More information on Japanese Knotweed

For more information on Japanese Knotweed, click on the links below