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myJapanese Knotweed Removal Cost
At a Glance
- The average cost to remove Japanese knotweed is around £6,150.
- Most jobs take 1 to 2 days to complete.
- Japanese knotweed cost breakdown by size, extent, and treatment type.
- How long the job takes and what's typically involved.
- How to find a local Japanese knotweed removal specialist using MyJobQuote.
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£6,150
Table of Contents
- How Much Does It Cost to Remove Japanese Knotweed?
- Types of Japanese Knotweed Treatments
- Labour Cost to Remove Japanese Knotweed & Timescales
- Factors That Impact Japanese Knotweed Removal Costs
- Japanese Knotweed Law and Legislation in the UK
- What's Involved in Removing Japanese Knotweed?
- Identifying Japanese Knotweed
- Giant Knotweed Removal Costs
- Checklist: Hiring a Japanese Knotweed Removal Specialist
- FAQs
How Much Does It Cost to Remove Japanese Knotweed?
Japanese knotweed is one of the most damaging and toughest plants in the entire world. It can grow at a menacing rate of up to 20cm per day, and can be incredibly challenging to eradicate.
Japanese knotweed can grow almost anywhere, including underground, up to a depth of 3 metres and can have a horizontal spread in any direction up to 7 metres. It can cause damage to concrete, house foundations, and patios by exploiting cracks and weaknesses.
If you discover Japanese knotweed growing somewhere around your property, it is essential that you act fast. If you leave this pest for too long, it can begin to grow underneath your home and even through cracks in your walls and floors.
There are a number of different types of Japanese knotweed removal and prices can vary from £1,000 all the way up to £20,000 for an average-sized garden in the UK. These prices will depend on the size of the infestation, the ease of access to your home, and the type of removal that you choose to carry out.
Emergency Japanese Knotweed Removal
An emergency Japanese knotweed removal will usually involve a full excavation and either a burial on-site or removal off-site. This is the fastest method for controlling and removing your Japanese knotweed invasion.
These types of excavation usually cost somewhere between £4,000 and £20,000 for an average-sized garden in the UK. The job will usually take just 1 to 2 days, depending on the extent of growth and the ease of access to your property.
Not every Japanese knotweed infestation requires emergency removal, but when a property is affected by structural damage, a sale is at risk, or mortgage lenders have flagged a Japanese knotweed problem, immediate Japanese knotweed removal is essential to prevent further damage.
I've been told I may have Japanese knotweed in the back garden, how do I go about checking this and then removing it? Do I need a specialist?
"You NEED a specialist to remove the knotweed as they need a licence to remove it from ANY property or land.
Make sure they are registered, as if someone removes it and doesn't have a licence to do so, then YOU would also be fined too, along with the company that removed it."
Make sure they are registered, as if someone removes it and doesn't have a licence to do so, then YOU would also be fined too, along with the company that removed it."
Japanese Knotweed Removal Prices
Below is a table of prices you should expect to pay for various parts of a Japanese knotweed removal and treatment job.
| Size of Treatment Area | Minor (<49m²) | Intermediate (50m² – 99m²) | Major (100m² – 499m²) |
|---|---|---|---|
| Herbicide Treatment | £1,000 – £2,950 | £3,000 – £4,950 | £3,950 – £6,950 |
| Sifting and Screening | £1,750 – £4,950 | £5,000 – £9,950 | £10,000 – £35,000 |
| Excavation and Root Barriers | £1,750 – £4,950 | £5,000 – £9,950 | £10,000 – £35,000 |
| Excavation and on-site relocation with ongoing herbicide treatment | £4,000 – £9,500 | £9,000 – £14,950 | £11,000 – £20,000 |
| On-site Burial | £4,000 – £14,950 | £10,000 – £20,000 | £15,000 – £35,000 |
| Full Excavation and Removal | £4,000 – £20,000 | £14,000 – £39,000 | £35,000 – £120,000 |
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In most domestic cases, a herbicide treatment is the easiest and cheapest solution to a Japanese knotweed problem.
Full excavation and Japanese knotweed removal costs vary widely within the same size area, depending on root depth, site access, and disposal costs for contaminated soil.
Japanese Knotweed Removal Cost per m²
Gardens come in all different shapes and sizes. To better understand the costs for Japanese knotweed removal from your garden, we've broken down the prices by m².
| Treatment Type | Approximate Cost per m² |
|---|---|
| Herbicide Treatment | £20 – £60 |
| Excavation & Root Barriers | £50 – £100 |
| On-site Burial | £80 – £200 |
| Full Excavation & Removal | £100 – £400 |
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These prices are approximate and can vary depending on site accessibility, infestation severity, any additional labour costs, and the overall treatment area, as larger areas often work out cheaper per m².
Types of Japanese Knotweed Treatments
There are a number of different treatments for Japanese knotweed. Below is a list of the different types of treatments that can tackle a Japanese knotweed problem.
Herbicide Treatment
A herbicide treatment is the most cost-effective Japanese knotweed treatment. For an average domestic garden, you should expect to pay around £1,000 to £2,950 for a herbicide treatment.
The treatment involves carefully and methodically managed visits where a chemical is sprayed onto and injected into the knotweed over a sustained period of time. This exhausts the plant and prevents it from spreading.
Excavation
Excavation is the fastest Japanese knotweed removal process, but it is also much more expensive than a herbicide treatment. For an on-site excavation with root barriers put in place to prevent the growth, you would be looking at paying around £1,750 to £4,950 for the work to be carried out on an average-sized garden.
The job involves using plant machinery to physically pull out the infected soil. Any traces of knotweed or infected soil will then be disposed of in a controlled process.
Sifting and Screening
Excavation can be a very large and costly job. The less contaminated the soil is that you have, the lower the costs will be for an off-site burial.
This is where a sifting and screening job comes in handy. For an average-sized domestic garden, sifting and screening will cost around £1,750 to £4,950.
The job involves using plant machinery to scrape back a thin layer of soil which is then sifted or screened by a Japanese knotweed surveyor. This involves digging out infested soil and screening it to remove the rhizomes.
The screened soil can then be re-used on a different area of the site, reducing the amount of waste that needs to be disposed of.
Burial on Site
An on-site burial saves the costs of having the infected soil and knotweed disposed of at a specialist landfill. Instead, the soil is buried on-site. The cost for an on-site burial on an average-sized domestic garden will cost around £4,000 to £14,950.
The job involves removing all of the infested soil and knotweed present and then burying these waste products at a different area on the site to a depth of around five metres.
This is a more cost-effective method than having the waste transported to be disposed of off-site.
Full Excavation and Removal Off Site
Sometimes the only way to remove your knotweed problem is to get rid of it through an excavation and removal of the waste off-site. A full excavation and removal off-site for an average-sized garden will cost around £4,000 to £20,000.
The process involves digging out and removing all of the existing knotweed and digging out any affected soil. These waste products will then be taken away and disposed of in a controlled manner at a specialist location away from the site.
Japanese knotweed removal costs at this level vary widely because roots can extend up to 3 metres deep, meaning a small area can require significant excavation, large volumes of contaminated soil removed to a specialist landfill, and disposal costs that quickly mount up, particularly where site access is restricted.
Labour Cost to Remove Japanese Knotweed & Timescales
Identifying and removing Japanese knotweed is not an easy job and is one that should be carried out by a professional.
Because this is specialist work, labour typically accounts for the majority of your overall quote.
A specialist Japanese knotweed contractor will charge around £20 to £50 per hour but labour costs vary depending on your location in the UK:
| Location | Hourly Labour Rate |
|---|---|
| London | £40–£50 |
| Berkshire | £35–£50 |
| Hampshire | £30–£45 |
| Somerset | £25–£40 |
| South Wales | £20–£35 |
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How Long Does Japanese Knotweed Removal Take?
The process of removing Japanese knotweed can take a long time. Here's what to expect:
- Initial Assessment — The contractor will need to attend the site to identify if the weed is actually Japanese knotweed and then they will conduct a plan with you to remove it.
- Treatment — The first stage will usually involve some removal and treatments with herbicide, and this part of the job will usually last less than a day for small areas such as domestic homes.
- Follow-up — This will usually not eradicate the problem completely. You should expect to have to have follow-up treatments for up to five years before your knotweed problem is completely taken care of.
Factors That Impact Japanese Knotweed Removal Costs
There are a number of things that may affect the cost of a Japanese knotweed removal job. Below is a list of things that may affect the cost of this type of job.
Size of the Affected Area
The size of the affected area will greatly affect the cost of your Japanese knotweed removal. For example, a herbicide treatment on an area below 49m² will cost around £1,000 to £2,950 whereas a herbicide treatment on a 500+m² area will cost around £5,000 to £12,000. So, you can see the size of the area can have a big difference in the cost of removing your Japanese knotweeds.
Type of Treatment Needed
The type of treatment needed in an area can affect the overall cost of the job. For example, a herbicide on an area below 49m² will cost around £1,000 to £2,950 whereas a full excavation and removal on the same size of area will cost around £4,000 to £20,000. So, you can see from this that the type of job required can greatly affect the overall cost of the job at hand.
Ease of Access to the Area
The cost can be affected by the ease of access to the area. If your property is located in an area that is difficult to access, this can result in the job taking a lot longer, and the labour costs will be greatly increased. On average, a Japanese knotweed specialist will charge around £20 to £50 per hour, and so additional time on the job can really add up.
Extent of Japanese Knotweed Growth
Similarly, the extent of the Japanese knotweed growth can affect the overall cost of the job. The more knotweed that needs to be treated, the longer the job is going to take, and therefore, the higher the overall cost will end up being due to the extra time and work needed.
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Japanese Knotweed Law and Legislation in the UK
Japanese knotweed is an invasive species of plant and, therefore, it is the responsibility of the landowner to ensure that this plant doesn't spread into neighbouring lands or into the wild.
There is no legal obligation to remove the plant as long as you are not encouraging the spread into neighbouring lands.
There are some rules in place regarding treatment and disposal:
- Pesticide Use — If you are using pesticides to treat your knotweed problem, you must ensure that you take all of the necessary precautions in order to protect human lives, animal lives, and plant lives. By law, anyone who is using a pesticide professionally must have the relevant certificate of the safe use of pesticides.
- Disposal — Disposal of Japanese knotweed must be carried out by a licensed waste carrier in a licensed facility. Transfer notes must be filled out and stored whenever Japanese knotweed is disposed of in one of these facilities.
- Fines — In 2014, the UK government brought out new legislation that states that anyone who fails to control Japanese knotweed from spreading could receive a Community Protection Notice. You could be fined if you ignore enforcement action.
What's Involved in Removing Japanese Knotweed?
Removing Japanese knotweed can be very tricky, particularly if there is a significant infestation.
It must be completely eradicated to ensure it doesn't return. As it's classified as controlled waste in the UK, all materials must be safely disposed of at a licensed landfill site.
In most cases, homeowners choose to hire a dedicated specialist, as it's the safest and most effective way to eradicate the plant.
With MyJobQuote, you can request several quotes from local Japanese knotweed removal specialists. It's fast, free, and there is no obligation to go ahead.
The most common approach used by professional contractors is herbicide treatment. The process is typically carried out as follows:
Before the Job Starts
- Risk Assessment — The removal specialist will begin with a full risk assessment of the surrounding area, evaluating any nearby schools, playgrounds, communal areas, or water sources that could be affected by herbicide drift. Neighbours may be notified in advance.
- Action Plan — An action plan is drawn up to outline all steps. The optimal treatment period is between late spring and early autumn, when the plant is in full growth.
- Weather Check — Weather conditions are checked before treatment. Herbicides can affect other plant life, so work is scheduled on dry, calm days to minimise drift.
During the Job
- Herbicide Application — Professionals typically use a garden sprayer or specialised tools near sensitive areas. Herbicides may also be applied using rollers, cloths, or brushes to protect surrounding plants or injected directly into the stems.
- Removal and Disposal — Any cut or removed knotweed is carefully bagged and taken to a licensed landfill site. Some UK councils offer specialist collection services, which contractors may coordinate with, where available.
After the Job
- Repeat Treatments — Complete eradication requires repeated treatments. Contractors typically repeat herbicide applications 2 to 3 times per year over 3 to 5 years until the knotweed is fully eliminated.
Identifying Japanese Knotweed
Japanese knotweed is a type of weed that spreads incredibly rapidly. It can penetrate through cracks and weaknesses in extremely tough materials, including flooring, walls, and roofs.
As an invasive plant species, it has a few specific features that make it easier to identify:
- Spring — Purple-reddish coloured shoots emerge from crimson-pink buds at ground level. Red-coloured shoots breaking through the ground are a good early indication of a knotweed problem.
- Summer — Bamboo-like shoots reach up to 7ft tall with noticeable purple spots. Heart-shaped or shield-shaped leaves grow up to 14cm in length with a zig-zag pattern along the stems.
- Late Summer — Clusters of cream-coloured flowers begin to show, attracting a lot of bees.
- Autumn — The plant dies back, leaving brown stems.
If you notice any of the above characteristics and are still unsure, you may want to hire a professional to inspect your area so that you can treat your weed problem as early as possible.
Are you obliged to hire a professional if there is Japanese knotweed in your garden? I am aware that you must not cut it, but what else must I do and must I not do if it ever pops up?
"Japanese knotweed can be an issue because it is a protected wild plant, but don't worry, if you do have problems in the future the environment agency can answer any problems you have."
Giant Knotweed Removal Costs
Giant knotweed is an invasive plant species closely related to Japanese knotweed, but grows significantly larger, reaching heights of up to 5 metres.
It can be identified by its much larger heart-shaped leaves, which can reach up to 40cm compared to the 14cm leaves of Japanese knotweed.
Giant knotweed removal follows the same methods, but the increased size and volume of growth mean giant knotweed removal costs will likely be at the top of the scale or higher. Key cost factors include:
- Bigger Plant — More plant material requires more herbicide treatment and longer treatment times.
- Larger Root System — Deeper roots mean more physical removal and a greater volume of contaminated soil.
- Disposal Costs — More plant material requiring removal to a specialist landfill.
Checklist: Hiring a Japanese Knotweed Removal Specialist
Below is a list of things to look out for when choosing the right Japanese knotweed removal contractors for the job:
- Are they qualified? Ensure they have the appropriate training and the correct pesticide qualifications if herbicide treatment is being used.
- Are they members of a recognised trade body? Look for membership of the Property Care Association or INNSA, as these are commonly associated with invasive weed work in the UK.
- Do they use professional grade herbicides? Ask which products they use and how they will protect surrounding plants during treatment.
- Will they provide a knotweed removal plan? A reputable Japanese knotweed removal specialist should provide a full knotweed management plan outlining the removal process.
- Will they take care of waste removal? Japanese knotweed is classified as controlled waste, so they must be a registered waste carrier and provide the relevant paperwork.
- Do they offer an insurance backed guarantee? Larger Japanese knotweed removal companies may offer this as added protection if the knotweed returns after treatment.
- Have they given you an itemised quote? Ask for a full breakdown of Japanese knotweed removal costs, so you know exactly what is included and whether there are any additional fees.
- Do they have examples of similar work? Take a look at the photos on their MyJobQuote profile for an example of their results.
- Do they have positive reviews? Check their MyJobQuote profile to read what other homeowners are saying.
FAQs
How Does Japanese Knotweed Spread?
Japanese knotweed does not spread via seed dispersion like other types of weed. It spreads through unintentional or deliberate movements of the plant’s chopped stems or fragments of the roots.
Can Japanese Knotweed Affect the Value of My Property?
Yes. Japanese knotweed is considered a serious issue for buyers and mortgage lenders. Properties affected by knotweed can be harder to sell, and lenders may refuse a mortgage until the knotweed is professionally treated and removed. A professional remediation certificate can help reassure buyers and lenders.
Do I Need Planning Permission to Remove Japanese Knotweed?
In most cases, you do not need planning permission to remove Japanese knotweed from your property. However, if your property is listed, in a conservation area, or if the removal involves substantial excavation or soil movement, it’s best to check with your local planning authority before starting the work.
How Can I Tell if Japanese Knotweed Is Still Present After Treatment?
Professionals typically monitor the treated area over several years to ensure the plant does not regrow. Signs of regrowth include new shoots appearing in the treated area. Even small regrowth should be treated promptly, as knotweed can rapidly spread and re-establish itself if not fully eradicated.
Can I Remove Japanese Knotweed Myself?
While the cost of a DIY treatment is lower than hiring a professional, there are risks involved, including potential harm to surrounding plants, soil contamination, and legal compliance issues. Professionals have the expertise, equipment, and legal knowledge to carry out the job safely and ensure all waste is disposed of at licensed landfill sites.
How Much Is a Japanese Knotweed Survey?
Japanese knotweed survey costs vary depending on the size of the affected area and the severity of the Japanese knotweed infestation. Most professional contractors will carry out an initial assessment before providing a quote for the removal process.
Is Japanese Knotweed Removal Covered by Home Insurance?
Home insurance does not typically cover Japanese knotweed removal costs, as insurers often treat it as a pre-existing condition. However, if a Japanese knotweed infestation has spread from neighbouring properties and caused structural damage, you may be able to make a claim.
Do I Have to Declare Japanese Knotweed?
If you are selling a house in the UK, you are legally required to declare a Japanese knotweed problem. Failure to declare it could be considered misrepresentation and may affect house sales or result in legal action from the buyer.
Why Should You Not Cut Japanese Knotweed?
Cutting Japanese knotweed can make a knotweed infestation significantly worse. Even a tiny fragment of the plant or root system can regenerate and spread quickly. Professional contractors have the appropriate training to treat the plant safely and prevent regrowth without risking further spread.
Will the Council Remove Japanese Knotweed?
Councils will only remove Japanese knotweed from public land they own and maintain. If the knotweed infestation is on private land, they will not remove it on your behalf, even if it has spread from neighbouring gardens, so hiring a professional contractor is your best option for Japanese knotweed removal.
