Japanese Knotweed Management in Ealing, Chiswick, Acton and Greater London


At APSL Japanese Knotweed Ltd. we specialise in Herbicidal treatment which is the most cost effective method in treating Japanese Knotweed and suited for areas where the ground is not going to be disturbed in the foreseeable future. It is a popular choice of knotweed control in urban areas, as most urban gardens do not often lend themselves to full excavation work with large machinery. There are several treatment methods for herbicidal control;

Stem Injection

Stem injection is a very successful method for treatment of knotweed in gardens and near water bodies. Stem injection is carried out by injecting a specific concentrated dose of herbicide into each individual knotweed cane. The benefits of stem injection is that the herbicides will be contained by the JK plant this will prevent damage to surrounding garden plants or waterways. The herbicide is absorbed deep into the rhizomes of the Japanese knotweed plant and kills the roots.

Stem injection is more cost effective then eradication. With eradication, all knotweed plant material and its surrounding soil needs to be brought, by licensed haulage transport, to a special licensed waste site that accepts knotweed material. Knotweed roots can grow up to 7 meters long and 2 to 3 meters deep, this can amount to a lot of plant matter and soil to be transported and deposited at special landfill at high costs. A geomembrane liner is often installed in the excavated area, preventing new knotweed growth to encroach into the area before it is refilled with new soil.

Stem injection is a longer process. It takes on average up to five years to manage a JK problem, three years of herbicidal treatment followed by two years of monitoring. Following PCA regulations, after herbicidal treatment there needs to be two consecutive years where no new knotweed growth appears before a completion certificate can be issued. Depending on the knotweed maturity and infestation, managing your knotweed problem could be a shorter or longer period.

Foliage spraying

Foliage spraying is a successful and economical method of treating larger knotweed areas. Herbicides are sprayed onto and absorbed by the knotweed leaves and then transported by the plant through the stem to the underground rhizomes. It is therefore important that the knotweed plant is at its optimum growth, at the end of its growing season, so that the herbicide can have maximum effect on the plants root system.

Leaf Wiping

Leaf wiping is mostly used for small knotweed growth. Herbicides will be “painted” on the leaves at the end of its growing season when it is in its optimum growth. The herbicide will be transported by the plant to its root system where its necessary effect takes place.

Herbicidal treatment and digging

A combination of two methods; digging is often used after herbicidal treatments has taken place. By digging the knotweed area, we can manually remove larger rhizomes and knotweed crowns. Digging can also stimulate knotweed growth to deeper dormant laying rhizomes by bringing it up to the surface. The new growth will be treated at the end of the JK growing season; digging can speed up the management of your knotweed problem.

How long does herbicide treatment take?

Herbicide treatment takes on average five years to complete depending on the Japanese Knotweed infestation at the property and surrounding areas. Knotweed control of a small area could be shorter; however, mature or larger knotweed areas could take longer to control.

Within the average five years knotweed control, there is a three-year treatment period, followed by a two-year monitoring period. By PCA regulations, once the herbicidal treatments are completed there should be two consecutive years of monitoring. If no new knotweed growth appears during these two years, a completed certificate can be issued.

Protective fencing

Protective fencing and signage will be installed around the knotweed-effected area. This should be kept in place until your knotweed is controlled. Note that this will affect the amenity use of these areas. Protective fencing is an important part of the knotweed management plan;

-It will prevent activity in the area, which could cause further JK spread. -It will protect the JK plants from being damaged ensuring herbicidal treatment can continue. -Signage will warn and remind the public that the area should not be accessed or disturbed. -Prevents knotweed plants from being strimmed or mowed, this will stop JK fragments being scatter elsewhere. -Prevents JK matter being spread elsewhere or taken off site. It is an offence under the Wildlife and country Act 1982 to spread knotweed into the wider environment or by the Environment Protection Act 1990 to allow controlled waste to leave the site other than by licensed carriers to licensed facilities.

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Contact APSL Japanese Knotweed Ltd.
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