Getting rid of Japanese knotweed is very difficult, to say the least.  The versatility and tough nature of this highly invasive weed plant not forgetting its ability to grow in various environments make it a menace.

Patience and consistency are vital virtues if at you intend to get rid of Japanese knotweed from your property.

Certainly, there is no quick-fix approach to eradicating this weed plant, however,  it is apparent that some methods relatively take a shorter time to deal with an infestation of the weed plant as compared to others.

Before we reflect on the duration various methods take to get rid of Japanese knotweed, here are the factors that greatly influence this situation:

Size of the infestation

Significantly, in places where the Japanese knotweed has rapidly spread such that it is growing in large-scale quantities, essentially, this implies that getting rid of the weed plant will take a longer time as compared to where a minimal infestation is present.

Japanese knotweed in the garden can cause both damage and legal issues
Japanese knotweed in the garden can cause both damage and legal issues

Area affected

It is relatively easier to get rid of Japanese knotweed growing in your private property or garden rather than one growing in a commercial or restricted area that may require licenses and various permissions from the concerned authorities.

Availability of resources

Fighting Japanese knotweed certainly requires one to set aside resources; financial, material, and human to effectively deal with the proper eradication of the weed plant for good.

The ease of access to such resources plays a big role in reducing the duration one has to use to get rid of the Japanese knotweed infestation on their property.

To get rid of Japanese knotweed you'll need a robust treatment plan
To get rid of Japanese knotweed you’ll need a robust treatment plan


Japanese knotweed is an invasive ornamental weed plant that you cannot wish away once it has infested your property. As soon as it hits the ground, you need to be ready with a quick action plan to eradicate this weed plant immediately.  

You need to be consistent in your approach towards eradicating the weed and your willpower must be strong enough to get you across the line, that is to say, full eradication has been achieved.

Availability of professional services

Occasionally, you may need to consult a professional on the best way to get rid of Japanese knotweed from your property.

If there are no such services available where you reside, then this means that your problem with the Japanese knotweed infestation in your property may take longer than expected or you may have to make do with methods that you are not certainly familiar with.

Notwithstanding the above factors, different approaches take different time frames to effectively get rid of Japanese knotweed. To better understand this phenomenon, the following segment will look into this in more detail based on the most common methods:

Developing a robust Japanese knotweed treatment plan will ensure you get rid of this persistent weed
Developing a robust Japanese knotweed treatment plan will ensure you get rid of this persistent weed

 Chemical treatment methods

The use of chemicals or what is better known as commercial herbicides is one of the common techniques for killing Japanese knotweed.

These herbicides have a non-restrictive use hence; anyone can readily buy and use them to eradicate the weed plant.

Although not cast in stone, where the weed plant has infested a smaller space, once you apply the herbicide, it is always advised that you must wait for at least 7 days to give the chemical time to work on destroying the weed plant.

If this period passes and you still note the presence of the Japanese knotweed on your property, you can re-apply the chemical to the unaffected weed plants until you get the desired results (eradication).

However, in instances where you choose to hire professional firms that specialize in the removal of the Japanese knotweed mainly because the infestation is large scale such that you cannot handle it individually, such firms will give you a working insurance policy of 3 to 5 years which will act as their guarantee to get rid of the Japanese knotweed from your property within the stipulated time.

Such a policy does not, however, imply that it will take up to 5 years for the weed plant to be eradicated; it is just a precautionary grace period just in case there is a new infestation within that period even after subjecting the weed plants to the chemical treatment.

Therefore, depending on the size of the infestation, when you apply chemicals to Japanese knotweed, it can take a period ranging from 2 weeks to 5 years depending on the scale of infestation.

Japanese knotweed treatment via spraying glysophate chemicals
Japanese knotweed treatment via spraying Glysophate chemicals

Physical eradication methods

Physical methods are those to do with actual human effort and skills to get rid of the Japanese knotweed.

The most common physical methods used to kill Japanese knotweed include; digging out the root system of the weed plant, covering it with barrier membranes, burning and burying, smothering, and mowing the weed plant.

The following segment will reflect which of these methods will take a shorter time and that will take a longer time to get rid of Japanese knotweed:

Short-term action

Digging out the root system and burning the Japanese knotweed approaches have almost an instantaneous effect as the life of the weed plant is killed immediately. Taking the roots out of the soil denies the plant moisture and the rich soil components to facilitate growth.

This essentially means that after the weed plant has dried up and disposed of the property, its growth is stopped within a short time. Burning on the other hand has the same effect of bringing an abrupt end to the life of the Japanese knotweed plant.

Therefore, these two methods can be said to have a quick effect on getting rid of Japanese knotweed if applied appropriately.

A short-term solution to get rid of Japanese knotweed
A short-term solution to get rid of Japanese knotweed

Long-term action

The use of barrier membranes, smothering, and mowing of the Japanese knotweed physical approaches do not have a fixed time frame in which one can say that complete eradication has taken place as a result of their application.

The reason for this is that these methods lean on the control aspect of the Japanese knotweed rather than the full eradication of it.

This is not to say that they cannot be used to get rid of the Japanese knotweed but one would have to wait for an unprecedented time frame to determine whether the applied method has worked and eradicated the weed plant in totality.

Want to know more about how to get rid of 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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Do not forget we have a library of blogs covering many areas relevant to Japanese Knotweed, our free downloadable How-to Guides and Product Reviews on the latest methods being employed to eradicate or remove Japanese Knotweed.

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