Japanese Knotweed Treatment Options
Preferred Treatment
Stem Injection
The preferred treatment method used by Japanese Knotweed Control is the stem injection process. Stem injection involves injecting a concentrate of glyphosate herbicide into each cane of the weed using specialist equipment specifically designed in the treatment of Japanese Knotweed.
Japanese Knotweed absorbs the glyphosate into the rhizome with a faster absorbency rate than that of folia spraying. Less risky to the environment, as the injected herbicide has no effect on the surrounding vegetation and is also safe to use near water, stem injection is a more effective eradication method.
Results will be seen within two weeks. From injection the weed goes dormant and visible signs of folia decay appear within days after treatment. Any canes missed during the process will be visible within the two-week period and a re-application carried out as part of the treatment process. Treatment is not affected by wind, rain or convection. Stem injection can be used at anytime during the growing season.
Common Eradication Treatments
Folia Application
Folia application is useful for large swathes of infested sites that are not ecologically sensitive areas nor subject to strict treatment deadlines. Folia spraying uses herbicides topically – the weed absorbs the herbicide through the leaves. As such this takes time for the weed to absorb the herbicide down to its rhizome. Only then does this ensure no re-growth occurs. A number of treatments are required for effectiveness and may take up to 24 months to complete. Folia spraying is dependent on weather conditions and only realistically effective, due to its growth cycle, in the Autumn.
Environmentally Sensitive Areas
We also specialise in the treatment of Japanese Knotweed on or near water by using the stem injection process, see right, which minimises any risk to water and the environment. We have experience in survey and license requirements and will ensure all documentation is filed and complete with the relevant government organisations.
Excavation
In time critical projects, it is possible to excavate the infestation for treatment later. In a controlled move the infestation can be quarantined within the site boundary, clearly marked and protected with a root barrier in place. The barrier would prevent further contamination, leaving the main site available for continued development. The infestation would be treated using stem injection at a later, more convenient time.
When the project is time critical and space restricted, it may be possible to excavate the infestation and then bury the contaminated soil in a sealed membrane capsule. The site must not be disturbed after excavation and re-burial and clearly marked on all deeds, plans and maps to prevent future disturbance and contamination. The Environment Agency must be notified prior to any on-site burial activity.
In extreme cases it may be necessary to excavate and remove contaminated soil off-site. This can be extremely expensive due to the amount of soil that would be need to be excavated as the root systems can grow to a depth of 3 metres and spread 7 metres. Excavations need to be strictly controlled and monitored to identify rhizomes. Such monitoring helps to minimise costs by reducing excess waste being taken off-site. All waste soil must to transported off-site by an approved contractor within covered or sealed wagons and taken to a licensed landfill. We provide a full document trail with all our operations and only use authorised carriers and landfill sites.
