Japanese Knotweed Removal | How to kill Japanese Knotweed?

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How To Kill Japanese Knotweed?

Known as one of the most troublesome weeds in the world, but how do you kill Japanese knotweed before it really gets out of hand? The invasive plant has been known to impact entire gardens, properties, development sites, and cause thousands of pounds’ worth of damage to buildings and underground utilities, when it hasn’t been eradicated early enough. Fully exterminating the weed has proved difficult due to the extensive rhizome network of roots associated with the plant.

Japanese knotweed is capable of growing rapidly in most environments and on average can grow some 4cm per day (and as much as 10-12cm per day in summer), resulting in a dense infestation in only a couple of weeks. More so, it only takes a small fragment of root or rhizome for the plant to grow and establish itself, either on a new or existing site. Knotweed fragments can be transported through soil importation, during construction, or even carried by footwear. Fortunately, with consistent and persistent efforts Japanese knotweed can be eliminated. Read on to find out the main methods for Japanese knotweed removal.

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The original Japanese Knotweed and Invasive Weed specialists in the UK, offering a full service from survey through to treatment and eradication including insurance-backed guarantees.

Using Herbicides

So, what chemical products can be used for Japanese knotweed treatments? Herbicides, including Glyphosate based products, are highly effective at eradicating this notorious plant. Glyphosate based herbicides are applied on the foliage of the weed using a sprayer after being mixed in a tank. The Glyphosate herbicide can also be injected into the stem. This method is most suitable for ecologically sensitive areas where spraying is not suitable.

It’s advisable to spray the Japanese knotweed through various stages of the plant’s development during the growing season. The infestation size, presence of watercourses and general public all have to be considered during herbicide selection.

Note that herbicide treatments do take time to work, and chemical treatments for Japanese knotweed eradication can take around 3 to 5 years to complete. Chemical treatment is considered the most cost-effective method and is favoured by domestic premises where the time factor for treatment may not be quite as important, say when compared with a development site where swift removal may be of vital importance so as not to hold up a building project.

Digging out Rhizomes

What about Japanese knotweed removal by digging it out? Rhizomes (the extensive network of underground roots) are very proactive in the spreading of Japanese knotweed. Therefore, excavating the rhizome fully and either disposing them to a licensed landfill facility or an alternative mechanical remediation strategy is one of the best ways of removing the plant. It is essential to ensure that all the pieces have been removed and a clean site policy is implemented to prevent cross-contamination.

Excavation is a highly effective but more costly method of Knotweed removal since it requires large amounts of soil removal over a wide area. It is usually the preferred option for those requiring quick eradication, such as developers, rather than for domestic gardens where it isn’t deemed necessary.

Clearance and Chipping of Japanese Knotweed

How can Japanese knotweed stems be disposed of? Chipping Japanese knotweed can be used as means of disposing of the stem cuttings to improve aesthetics and to facilitate access to the infestations. However, it is important to ensure that the cuttings have sufficiently dried out before being chipped to prevent regrowth. Ideally these works should be undertaken within the winter period. Chipping on-site should be done in a controlled way to avoid cross contamination.

Chipping on-site has replaced on-site incineration as a more environmentally friendly method of disposal. If the stems are to be chipped, it is vital that this is done in the winter months once the stems have died and dried to make sure they have no chance of spread or regrowth.

Using MeshTech Removal Method

What eco-friendly ways are there for Japanese knotweed treatment? The MeshTech method is an eco-friendly means of controlling the spread of Japanese knotweed. Designed by Dr Eric Connelly and JKSL, the method does not use any chemicals, and therefore leaves the lowest possible on-site footprint where it is used. It is also useful in preserving soil fertility and controlling soil erosion, especially along river banks.

MeshTech is effective as it forces the plant to sever its own stems on a wire mesh placed over it where it grows. This exposes the plant, leaving it open to damage by frost and rot. Eventually the Knotweed plant will die off due to exhaustion of the nutrient stores in its root system.

MeshTech can be a preferred methodology over herbicide use because it ensures that the surrounding environment remains as unaffected as it can be, conserving animal and plant life. It is an ideal deal technique for Japanese knotweed eradication in ecologically sensitive areas such as riverside locations, railway embankments and highways.

Biological Control of Japanese Knotweed

Can biological methods be used for getting rid of Japanese knotweed? Although still being trialled, the biological method is one of the environmentally-friendly methods of dealing with Japanese knotweed. This method of control relies on the use of a tiny sap-sucking insect called the psyllid, which lays its eggs on Knotweed. The young nymphs eat the plants, preventing them growing any taller, and this drains the life out of the weed.

JKSL closely follow the research work of CABI (Centre for Agriculture and Biosciences International) and DEFRA (The Department for Environment, Food and Rural Affairs), who began the psyllid release programme way back in Spring 2010 at several sites across England and Wales. A natural predator, the psyllids insect, has been discovered as a method of naturally keeping the plant under control.

Biological control will not kill Japanese knotweed, but can slow the spread of the plant and make it more vulnerable to chemical control. The risk of damage to native plant species has been found to be low, meaning it could open the door to more biological control against Japanese knotweed and other invasive weeds. The hope is that the insects could eventually establish themselves across the nation to slow the spread of Knotweed.

Conclusions About Japanese Knotweed Removal

There are several methods of Japanese knotweed treatment that are successful. (Find out more about potential Japanese knotweed removal costs.) Eliminating the weed often requires a multi-pronged approach by applying different methodologies.

Whether you choose chemical or mechanical methods of getting rid of Japanese knotweed, the job should always be handled by professional Knotweed removal experts. Often, hiring a professional service such as JKSL for Japanese knotweed removal is the only way that you can be sure the weed and its roots have been completely eradicated.

If you are still unsure of the best method of Japanese knotweed removal for you, then get in touch with JKSL. We can help you with Japanese knotweed identification to determine if you have a problem, and then give you advice on the Japanese knotweed treatment options best suited to your particular situation.

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