Ben Lindley, Company Director at Japanese Knotweed Ltd.
Last reviewed on 29th October.
How to Find a Trusted Japanese Knotweed Contractor for Development Sites
In this article we’ll show you what developers should look for in a knotweed contractor. Japanese knotweed, as most UK developers are aware, is a serious issue. Suspecting it or finding it on land planned for development can delay projects, increase costs, and cause compliance risks if not handled correctly. Finding a qualified, accredited contractor is therefore a number one priority for safe, legal, and lender-approved remediation.
In this article we list what developers should look for when choosing a knotweed removal supplier with the right industry accreditations and qualifications.
Property Care Association (PCA)
For most residential developments, PCA membership is a minimum requirement.
The PCA is the most recognised authority for Japanese knotweed management. Its ensures its accredited members are:
- Independently audited and insured
- Trained to PCA standards
- Able to issue Insurance-Backed Guarantees (IBGs)
- Accepted by mortgage lenders, NHBC, and LABC
Warranty providers such as NHBC, LABC Warranty, or Premier Guarantee all require knotweed contractors to be PCA members.
Procurement Platforms – verified contractors
Large house builders typically vet contractors through accreditation portals such as:
- Constructionline
- Builder’s Profile
- CHAS
- SafeContractor
These accreditations run rigorous, industry specific checks to ensure suppliers meet insurance, health & safety, and environmental competence standards. It’s important for contractors to update their supplier assessments yearly to remain compliant and certified with these organisations.
Industry accreditations
Acclaim Accreditation is a Safety Schemes in Procurement (SSIP)-approved health & safety assessment scheme, managed by Constructionline. It’s widely accepted by developers, councils, and principal contractors as proof that your business meets core health and safety standards.
Achilles is one of the UK’s leading supply chain assurance platforms, widely used by house builders, local authorities, utilities, and infrastructure firms.
Holding Achilles and Acclaim SSIP accreditations shows the knotweed business is:
- Professionally managed and safety-compliant
- Ready to work on major frameworks and public contracts
- Environmentally responsible and fully auditable
Japanese Knotweed Ltd holds the following industry accreditations:
- ACHILLES
- ACCLAIM
- AMENITY ASSURED
- BASIS
- BUILDERS PROFILE
- CHAS (SSIP)
- CONSTRUCTIONLINE GOLD (SSIP)
- CQMS (SSIP)
- FACILITESLINE GOLD
- PCA
- PROSURE 360
- SAFE CONTRACTOR(SSIP)
- SMAS (SSIP)
Required qualifications
The main professional standard for knotweed contractors in the UK is PCA membership.
To become PCA-accredited, a company must:
- Employ qualified surveyors and technicians
- Hold appropriate insurance and health & safety policies
- Pass independent audits of documentation, training, and performance
- Follow the PCA Code of Practice
Why it matters: PCA accreditation is recognised by lenders, NHBC, and LABC. It’s the benchmark for professionalism in invasive weed management.
To work with or apply herbicides, survey, and manage Japanese knotweed, individuals typically need the following 3 types of qualifications:
NPTC / City & Guilds PA Qualifications
Issued by City & Guilds Land Based Services, used for safe and legal use of pesticides and herbicides.
- Common certifications:
- PA1 – Foundation in the Safe Use of Pesticides
- PA6 – Hand-held applicator (knapsack sprayer)
- PA2 – Boom sprayer (tractor-mounted)
- PA6AW – Application near or over water (if treating knotweed near waterways)
- These are legal requirements under the Plant Protection Products (Sustainable Use) Regulations 2012.
For contractors working on construction or development sites, they’ll also need:
- CSJK
- CSCS card (Construction Skills Certification Scheme)
- SSSTS / SMSTS (Site Supervisor / Manager Safety Training Scheme) for supervisors
- Demonstrable competence under CDM 2015 Regulations
Japanese Knotweed Ltd teams are fully qualified with the above which means we can carry out all aspects of Japanese knotweed control and removal, from professional identification, survey, treatment applications and excavation.
Insurance and Guarantees
Professional contractors must carry:
- Public Liability Insurance (typically £5–10 million)
- Product Liability Insurance (typically £5–10 million)
- Professional Indemnity Insurance (especially for survey/report writing)
- Ability to provide an Insurance-Backed Guarantee (IBG) underwritten by an FCA-regulated provider
Japanese Knotweed Ltd is fully insured up to £10 million.
Darren Greatbatch, Specialist Advisory Manager, Japanese Knotweed Ltd states “It’s imperative that the right company is chosen with correctly trained and certified staff that can identify not only a specific invasive weed specified by the client but a wider range of target species. The biggest threat to developers that we’ve seen this year is Horsetail. We hear about developers using scraped topsoil for gardens on completed housing projects which contain fragments of invasive plants such as Horsetail that then grow and cause issues for the new owners. We strongly advise a pre-planning survey to note ALL invasive species that could be dealt with at the right time – and prior to build commencement.”
If you’d like to speak to us about our professional knotweed removal services, or get a no-obligation quote contact the team.