Knotweed Removal Methods
Knotweed Removal Methods
Cutting Edge Innovation by London's Leading Knotweed Removal Specialist
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We are specialist knotweed removal contractors with the experience and expertise to handle small and large infestations of Japanese Knotweed.

GardensJapanese Knotweed Removal Techniques
  • Herbicidal Spraying
  • Herbicidal Stem Injection
  • Herbicidal Leaf Wipe Foliar Application
  • Excavation - Dig and Dump
  • Excavation - Stockpile and Bund
  • Excavation - Screening & Sifting
  • Excavation - Cell Burial
  • Root Barriers
  • Psyllid Insect Control
  • Animal Grazing
  • Burning

A popular solution for residential clients and local councils is herbicidal stem injection. The knotweed will need to be treated over a minimum of three years to ensure eradication. Knotweed on construction sites needs to be handled differently because of the time constraints

. A combination of removal techniques is normally used, ranging from excavation, herbicidal treatment and long term site monitoring.

Please do not hesitate to get in touch if you think we may be able to help you.

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Customer Testimonials

Herbicidal Spraying

Spraying should only be used were there is no risk of contaminating waterways, animal and plant life.

If spraying is to be the only method of eradication used, then four applications over the growing season ( April-Oct) will be required, followed by further treatment in subsequent years.

Herbicidal Spraying

Herbicidal Stem Injection

Of all the herbicidal application methods we have tried, our research and experience tell us that Herbicidal Stem Injection is by far the most effective treatment available.

In a city environment it is essential to ensure that the herbicide used does not contaminate the surrounding plants or waterways. Stem Injection is the perfect solution.

Stem Injection

Excavation - Dig & Dump

Even a small stand of Japanese Knotweed will have roots which go down to 3 metres and can spread out around the plant to a distance of 7 metres.

This means that excavation of the plant involves digging out 20 tonnes of soil which has to be removed to landfill and them replaced with clean soil - Expensive

Dig & Dump

Excavation - Soil Screening

The knotweed infested soil is dug out. It is then mechanically and manually screened to remove the rhizomes.

These are taken to the landfill site and the screened soil is used elsewhere on the development. We advise that the screened soil is used in soft landscaping areas. When done properly it is a sustainable solution and very cost effective.

Soil Sifting and Screening

Excavation - Cell burial

This involves moving knotweed contaminated soil from one part of the construction and burying it in a excavated pit lined with root barriers on another part of the site.

The Environment Agency recommends that the top of the burial cell should be a minimum of 2 metres below ground level. The overall depth of the burial pit should be in excess of 5 metres deep

Cell Burial

Root Barriers

Root barriers, as well as being used to aid cell burial of Japanese Knotweed on construction sites, can also be used to prevent the spread of Knotweed onto neighbouring land.

The root barrier is normally installed vertically along the boundary to a depth of at least two metres. Root barriers can also be used horizontally to stop the knotweed from growing up through tarmac, driveways and patios.

Root Barriers

Psyllid Insect Control

Scientists working for CABI, the Centre for Agricultural and Bioscience International, have identified a 2mm long psyllid insect, found in Japan, known as Aphalara itadori, that lays its eggs exclusively on Japanese Knotweed.

When the young hatch, the larvae guzzle away on the sap produced by the Japanese Knotweed plant. The grubs have a voracious appetite and put the knotweed under considerable stress - preventing it from spreading - or at least that is the hope.

Psyllid Insect Control

Animal Grazing

Farmers and land owners will be pleased to learn that animal grazing can be used as a control method for Japanese Knotweed. Continual grazing will prevent the knotweed from spreading and becoming a nuisance. It is not a method of total eradication

Using Japanese Knotweed as animal fodder is common practice in Asia. Cows, donkeys, horses, sheep and goats will happily graze on Knotweed. It can also be used for human consumption and there are even recipes for it's use as food and even as medicine.

Animal Grazing

Stockpile and Bund

The contaminated soil is excavated and moved to another part of the site. It is spread out to around half a metre in depth on a geo-textile membrane, treated with herbicide and monitored for up to three years.

The area can be surrounded by a concrete bund or root barrier, down to a depth of 3 metres.

This method of treatment is usually only practical on larger construction sites.

Stockpile and Bund

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