Successful Japanese knotweed removal methods are important to prevent the devaluation of your property or any possible legal action being taken.

In this article, we aim to give a rough idea of costs per method to remove Japanese knotweed. However, a word of caution, prices can vary between contractors and areas, so all prices we give are a guide at best.

1) How much does it cost to have Japanese knotweed removed by herbicide?

The first method is removing the roots by hand, which is usually free but can cost money if you have a lot of knotweeds to remove. However, this is not the only way to remove Japanese knotweed. The most common and preferred method for homeowners is by using herbicide – specifically glyphosate.

Glyphosate has been used successfully all over the world on Japanese knotweed, with excellent results. However, it must be remembered that no chemical can give 100% success so there are always methods that you can use to improve your chances of eradication.

The cost of having Japanese knotweed removed by herbicide is quite high – but surprisingly not as high as some people think.

The reason for this is that glyphosate is available in many local garden centres or on Amazon, not just from specialist suppliers or firms which are licensed to purchase it on your behalf (and therefore charge you more). This means that if you go to your local garden centre or Amazon, they may sell glyphosate for about £8 per 500ml bottle of a concentrated product.

How much it would cost to remove Japanese knotweed with this method?

A 500ml bottle will cover an area of approximately 20 square metres so we would recommend that you always try and get a larger bottle if it’s reasonably priced. If you can afford to do so, we would recommend getting 2 x 1-litre bottles which will cover an area of 40 square metres.

Once mixed with water to the concentration rate of 41% (please read this article where I explain the concentrations), this will cost approximately £16. So, if you were treating 20 square metres, the total cost would be £32 to treat your Japanese knotweed with herbicide.

For 100 square metres, this is obviously 10 x as much (i.e., it will cost £320). If you multiply the number of square meters by 32 it should give you an indication of how much it would cost to remove Japanese knotweed in your garden. You can obviously spend more if you choose to do so, but this is the average price.

2) How much does it cost to have Japanese knotweed removed by excavation?

This is the most expensive method of removing knotweed. However, before I explain how much it would cost to remove knotweed via excavation, you need to know that this is the only method that guarantees 100% eradication – no other methods are guaranteed.

This is why it’s very important that before you spend any money on removing Japanese knotweed, you must be 100% sure that the roots are removed completely because once they’re gone, they’re gone.

Excavating Japanese knotweed is a very detailed job and it can be quite costly too. However, if you have the money to spend on digging up your garden, here’s how much it would cost:

The price of excavating a 1-metre squared area of a lawn where knotweed has grown is around £74

The price of excavating a 1-metre squared area where Japanese knotweed was found growing through the patio or path is £148

So, to remove Japanese knotweed by excavation will cost you between £162 and £220 per square metre depending on what exactly your problem is. This means that if you were to excavate 100 square metres of knotweed-infested land, you would spend between £16,200 and £22,000.

If you wish to use this method in your garden (and I recommend that if you can afford it and want 100% eradication – it’s the only way), please take a look at this very detailed post on how much it would cost you to excavate your garden.

3) How much does it cost to have Japanese knotweed removed by the root?

If you want to remove Japanese knotweed, one of the most effective methods is also the cheapest. This method only costs £50 per square metre and if done correctly, has a very high success rate.

In order to have Japanese knotweed removed from your garden by ‘root’, you need to use a method called heat treatment. This is a legal and safe way of removing knotweed without using any chemicals or causing any harm to the environment so is highly recommended if you don’t want to spend too much money on removing Japanese knotweed from your garden.

The heat treatment method will cost just £50 per square metre and the way it works is that a deep trench is dug out around where the knotweed is growing. The soil from this trench is then placed into a container that has been previously brought to a high temperature, usually by being placed either in a large incinerator or by being placed in a container that has been heated with gas.

Once the soil has cooled down, it is distributed back into the trench.

4) How much does it cost to have Japanese knotweed removed by excavation and ground injection?

This is the most effective method of treating Japanese knotweed as it uses a combination of three different methods to kill knotweed.

Excavation is used to remove the majority of the weed, then the ground injection is used to ensure that the soil remains clear of Japanese knotweed for years after treatment has taken place.

This method will cost around £194 per square metre and the reason why it’s so expensive compared with other methods is that each job is different and the cost of excavation, ground injection and any other additional measures taken to ensure that Japanese knotweed doesn’t return is based on a number of factors including the size of your garden, how thick the knotweed was growing etc.

5) How much does it cost to have Japanese knotweed removed using herbicides?

This method is the least effective but also one of the cheapest. It’s not recommended by us because if you’re unfortunate enough to not kill the knotweed using chemicals, you won’t be able to remove it yourself and will need to pay for excavation or ground injection.

Other ways of removing Japanese knotweed

Japanese Knotweed is a weed that can be removed by digging it out and you could also use the method of ground injection to kill it.

However, these methods are not always successful and it is best to go with one of the five choices first if really wish to remove Japanese knotweed from your property.

Want to know more about Japanese knotweed removal methods?

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.

The best means to contact us is via our email –

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.

Knotweed Removal, UK

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