Ben Lindley, Company Director at Japanese Knotweed Ltd. Last reviewed on 15th October 2025.
In this article, we outline Japanese knotweed removal costs, dependent on the treatment or excavation method you opt for and other common considerations
HOW MUCH DOES JAPANESE KNOTWEED HERBICIDE TREATMENT COST?
If you’re happy to have a longer-term in-situ solution, knotweed can be controlled through a series of herbicide treatments delivered at the best time of the year for the herbicide to be effective. Costs are usually detailed in a Knotweed Management Plan which will also outline the treatment schedule. The quote usually follows a site or property survey carried out by one of our qualified surveyors, and all findings from the site survey will be included in the management plan document.
We provide 5 or 10 year term plans, with a 10 Year knotweed management plan recommended for residential property. Ideal for buyers and sellers, as well as long-term homeowners who want to ensure the knotweed is gone from their property, this provides a professionally delivered herbicide treatment programme with an insurance-backed guarantee that is accepted by property surveyors and mortgage lenders.
Herbicide treatment is the most cost-effective way to deal with Japanese knotweed. Plans for small infestations can typically range between £1,800 and £2,500, but always seek a survey and quote from a professional. Do not attempt to use controlled herbicides yourself without the correct training and personal protection equipment.
The larger the infestation, the greater the cost and other considerations including requirements for 2-person working (to satisfy health and safety concerns, such as work on steep slopes) will impact on cost as well.
Herbicide control plans are appropriate if accompanying long term restrictions on the use of the treatment area are desirable, and there are no plans to disturb or change the use the treatment area (i.e. development).
Want to know what to do if you and a neighbour has knotweed? We offer a discount to both properties. Find out more:
HOW MUCH DOES JAPANESE KNOTWEED EXCAVATION COST?
If you want to permanently get rid of Japanese knotweed (i.e. eradicate the problem), then excavation is required. Excavation of Japanese knotweed removes the plants underground rhizome system, from which the plants grows and spreads. The underground rhizome system spreads out further than the visible above ground extent of the plant and requires an expert eye to ensure the rhizome is correctly identified and removed. Excavation can be carried out on residential properties as well as commercial land/property and development/construction sites, and costs will depend on the following factors:
- The size (area) of knotweed infested ground s.
- Volume of knotweed contaminated soils to be excavated.
- Method of waste disposal, with options to remove to landfill, or bury or relocate onsite.
- Site specific considerations – such as retained trees or underground services.
- Environmental factors – such as protection of endangered species.
We need to survey the site before providing a cost for excavation as there are many factors which can affect the cost of works. Once we have all the information we need, including your requirements, we can provide a knotweed management plan document that will include all survey findings, our site specific recommended excavation method options, and of course our costs.
We’re experienced, qualified, funded and licensed to handle contracts of all sizes, for all types of clients, on all types of sites. The smallest of excavations will typically cost from £4,000 and a history of excavation contract values undertaken generally ranges from £4,000 up to £150,000 depending on the work in hand.
Occasionally we complete some really large contracts including a single excavation project on HS2 completed for just under £1.5 million. We utilised a methodology which reportedly saved the client an estimated £1.8m in comparison to more traditional remediation approaches (assessment made by project consultant AECOM).
In summary
The cost of Japanese knotweed removal requires careful consideration of all factors listed in this article (sometimes more). Attempting to deal with knotweed yourself to save money comes with serious risks like causing it to spread to a neighbouring property or making the problem on your own land even worse. Using a specialist knotweed contractor to survey and quote will enable you to make a fully informed decision. We’re here to help with any questions you may have. Speak to the team today and be knotweed savvy!
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