Japanese Knotweed is an invasive plant species in the UK that, due to its aggressive growth, can affect property values and mortgage approvals.

It must be declared on the TA6 form when selling a home, making its removal a crucial concern for homeowners.

Japanese knotweed removal costs vary depending on the method used. There are two main options: herbicide treatment, which involves repeated applications to control growth, and excavation, which involves physically removing the plant and its roots.

The cost of each Japanese Knotweed removal method varies depending on the size of the infestation and the site conditions.

Herbicide Treatment

Herbicide treatment for Japanese Knotweed is generally the most cost-effective removal method, with costs ranging from £1,000 to £6,000 for a comprehensive management plan that includes multiple applications over several years.

For one-off herbicide treatments, costs are around £120 + VAT per session.

The price varies depending on factors such as the size of the infestation, the number of required herbicide treatments, and site conditions.

Effectiveness and Application

Herbicide treatment involves systemic herbicides like glyphosate, which penetrate the leaves and reach the plant’s root system.

Studies show that sustained herbicide use can reduce Japanese knotweed biomass by up to 85% over three years, but complete eradication often requires ongoing efforts.

Advantages: Lower cost, less invasive than excavation, suitable for large areas.

Limitations: Requires multiple treatments over several years, may not achieve total eradication, and can impact nearby vegetation.

Herbicide treatment is an affordable, practical option for managing Japanese Knotweed, particularly when immediate removal isn’t required. However, it requires consistent application and patience for long-term control.

Excavation and Disposal

Excavation and removal are often necessary for severe Japanese Knotweed infestations, especially when immediate removal is required or construction is planned.

The costs of Japanese excavation can range from £7,000 to £15,000 + VAT for residential sites.

These costs depend on factors like the size of the infested area, soil volume, and site accessibility. Excavation is generally more expensive due to the labour-intensive process and the need to dispose of Knotweed-contaminated soil in compliance with strict regulations, which adds to the overall cost.

Effectiveness of Excavation

Excavation involves physically removing the plant and its extensive rhizome system from the ground.

This method is one of the most effective ways to prevent Japanese Knotweed from regrowing, as it targets the root system directly.

According to a review by the UK Environment Agency, excavation can, when done correctly, reduce knotweed regrowth by up to 95%.

Advantages: Excavation offers immediate and highly effective removal of Japanese Knotweed, especially suitable for development sites requiring rapid clearance.

Limitations: excavation is costly due to labour and disposal fees, can disrupt the surrounding area, and requires strict regulatory compliance for soil disposal.

Studies and industry reports have demonstrated that excavation provides a faster solution than herbicide treatments. The Environment Agency’s Knotweed Code of Practice outlines best practices for excavation, highlighting its effectiveness and emphasising the importance of licenced disposal to prevent further spread.

Excavation is a highly effective, though costly, method for removing Japanese Knotweed, especially in urgent cases; however, ongoing monitoring and follow-up treatments are often needed to ensure complete eradication.

Japanese Knotweed Removal Pricing Table

Find out the estimated costs for treating Japanese Knotweed based on the size of the infestation and type of property.

The table below provides a clear breakdown to help you understand what you might expect to pay for different knotweed treatment methods.

Size of Infestation	Domestic Houses	Commercial Sites: Herbicide Treatments (5 years)	Other Methods (Reduced Dig, Root Barriers, etc.)
Area (0-5m²)	£1,000 – £2,000	£1,500 – £3,000	POA
Area (5m² – 10m²)	£2,500 – £3,500	£3,500 – £4,500	POA
Area (<10m² – 20m²)	£3,500 – £4,500	£4,500 – £5,500	POA
Area (20m²+)	£4,500 – £8,000+	£5,500 – £8,500+	POA

*POA: Price on Application

Please note that actual costs may vary depending on site conditions and requirements.

How Long Will The Knotweed Removal Process Take?

The duration of Japanese Knotweed removal depends on the chosen method. Herbicide treatment usually requires 2-5 years of repeated applications to manage regrowth effectively.

Excavation and removal are faster and often completed within a few days to weeks, but they may still require follow-up monitoring to ensure no regrowth.

What Are The Guarantees Or Warranties Provided On Knotweed Removal?

We offer a guarantee of up to 10 years for our premium Japanese Knotweed removal services, covering any regrowth within that period.

This guarantee applies to herbicide treatment plans and excavation services, provided the terms and conditions are met. It offers long-term protection and peace of mind.

Are Follow-up Inspections or Treatments Included in the Cost?

Our comprehensive removal plans include follow-up inspections and treatments to ensure effective management.

This involves periodic site visits to monitor progress and apply additional herbicides as needed for herbicide treatments.

At the Japanese Knotweed Survey, we monitor excavation, including checking for regrowth at regular intervals.