There is a multiplicity of methods on how to kill Japanese knotweed with each having different results based on its application.  For that reason, this article will deliberate on the best methods available on how to kill Japanese knotweed expeditiously.

Physical removal methods

This method largely involves the use of human physical effort to get rid of the invasive weed plant from their property. The physical methods work towards the elimination of the canes that have grown above the ground together with the underneath root and rhizome system.

On this footing, the best physical methods to be considered are as follows:

Cutting and extracting

Cutting works on the stem of the weed plant but not the root system hence the need to use these two methods alongside each other.  When cutting the canes of the Japanese knotweed, it is advisable that this is done as close to the ground as possible and accurately.

You need to be cautious not to scatter the fragments of the plant all over. After cutting, the next course of action would be to extract the underground root system of the weed plant.

Where the plant is relatively at its early stage of growth, you can try to pull it from the ground with your hands, however, if the plant is fully grown such that the roots are ingrained into the soil, you can use home-based tools such as a shovel or in extreme circumstances that require very deep extraction, you can choose to get machines (excavators) to do the job for you.

Notably, excavation has its fair share of spoils, for instance, it can lead to damage to the garden due to the heavy digging involved, and, as a consequence one may incur additional costs of restoring such a place to its original state.

Dig and dump

This is mainly to do with the removal of the infected soil as a result of the previous presence of Japanese knotweed. Even after cutting and excavating the invasive weed plant from an area, it is possible to find that the soil contains fragments of the weed plant’s rhizomes and roots.

Although not cast in stone, it is prudent that the associated infected soil is dug out and taken to licensed disposal zones. By doing this, you are practically sealing all the loopholes of a potential regrowth from any left fragments in the soil.

How to get rid of Japanese knotweed by digging it out
How to kill Japanese knotweed by digging it out

Burning and burying

The waste remains of the cut and dug-out Japanese knotweed can still grow when left unattended. This makes it vital that the disposal of such remains becomes a necessity.

Disposal by way of burning involves the use of incineration equipment that will subject the remains to very hot temperatures such that nothing survives the process.

Experts advise that incineration should not be done in an open space as this may lead to emissions and worst-case scenario the remains may be blown away by the wind when not fully burned hence risking the possible risk of growth elsewhere.

The burnt remains must also be transported to an authorized land site that is licensed for the final disposal.

Burying, on the other hand, can either be done in the area of removal of the weed plant; the reason being to avoid the possibility of transferring rhizomes to a different place and invoking a fresh growth or in a site that is approved for such a purpose.

The most important thing to note is that any waste material from the weed plant to be buried must never be mixed with any domestic waste as this may invoke fresh growth of the Japanese knotweed.

Secondly, the waste that remains to be buried must be put inside containers or plastic material that can be completely sealed. There should not be any room for escape if the rhizomes of the cut weed plants grow.


This method involves the use of home-based tools or a mowing machine to cut down Japanese knotweed that is in its early stages of growth. Mowing must be done consistently for it to be effective. 

Chemicals and pressure sprayer required to remove Japanese knotweed off your property
Chemicals and a pressure sprayer are required to remove Japanese knotweed off your property

Herbicide treatment

Normally, herbicides are chemical elements that are commercially manufactured for the very purpose of defeating different weeds including the Japanese knotweed. This part will deal with how to kill Japanese knotweed using herbicides:

Types of herbicides – there are a variety of herbicides available for the treatment of Japanese knotweed; however, the recommendable ones are those that contain glyphosate (this does not necessarily undermine any available herbicides in the market).

Application methods – herbicides must be sprayed directly on the weed plant preferably after cutting has taken place or in some instances, they can be injected into the stem of the weed plant.

Additionally, at least 7 days must be allowed for the herbicides to work their magic on the weed plant before the dead remains are pulled out. Notably, it is paramount that one wears protective gear when using any form of herbicide.

Burying Japanese knotweed underneath an impervious membrane
Burying Japanese knotweed underneath an impervious membrane

Use of membrane barriers

One may wonder how to kill Japanese knotweed using membrane barriers but this method has proved to work if put to proper use. Preferably, barriers should be used either when the cutting of the invasive weed plant has taken place or when the plant is at its early level of growth.

Just like any other plant, the Japanese knotweed heavily requires enough sunlight and water for growth; therefore, denying it such luxury impedes its rapid growth.

The membrane barriers should be positioned on the soil surface leaving the weed plant underneath it deprived of sunlight. Heavy objects should be put on top of the membrane to avoid them from being blown away.

Membranes should also be placed on the periphery areas of the land to avoid rhizomes escaping sideways in search of precious sunlight for their growth.

Combined methods

Experts across the board support the idea of having a combination of methods when it comes to the full eradication of Japanese knotweed.

In most instances, when two or three methods are applied consecutively, they work perfectly towards the elimination of the Japanese knotweed as compared to a scenario where only one method is considered.

Want to know more about how to kill Japanese Knotweed?

Knotweed Removal aims to provide the most up-to-date information, help and advice for YOU to make informed decisions. If you are unsure or uncertain about how to proceed, please reach out to us and we will gladly come back and advise you as best we can.

Governmental advice can be found here and the UK law covering the removal of Japanese Knotweed as stated under the Wildlife and Countryside Act 1981 can be found here.

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