Before the Jones et al. (2018) research, the UK Japanese Knotweed industry was undermined by a lack of empirical data, leading to the use of untested, ineffective, and expensive control methods. The UK Government had even withdrawn its ‘Knotweed Code of Practice’ in 2016 due to increasing civil liability claims and the absence of clear scientific guidance for herbicide selection.
Brief
The research team aimed to:
Identify best practices for long-term Knotweed management through the largest infield assessment of control methods ever conducted.
Provide a benchmark standard for civil court cases involving Knotweed encroachment and mismanagement.
Address the legal ambiguity in property transactions regarding the ‘eradication’ of dormant belowground rhizomes (roots).
What we did
The project combined decade-long field research with high-level policy engagement:
The Global Field Trial – tested 19 marketed treatment methods on 225m2 plots over several years, identifying that effective control is achieved through specific glyphosate applications timed to the plant's internal mass-flow movements (the ‘Four-Stage Model’).
Founding of Advanced Invasives – following the initial research phase, Dr Daniel Jones founded Ai to deliver this evidence-led guidance to major landowners and the legal sector.
Legislative advocacy – engaged with the House of Commons Science and Technology Select Committee and the Law Society to demonstrate that ‘eradication’ was an inappropriate legal term, given that rhizomes can remain dormant but viable belowground.
Guidance development – produced bespoke community and industrial guidance adopted throughout Wales and the wider UK to raise public awareness and standardise treatment protocols.
Key Outcomes
The research has had a profound socio-economic and legal impact across the UK:
Legal changes – the Law Society updated the TA6 Property Information Form (4th edition, 2020) to include a ‘don't know’ option regarding knotweed presence and replaced the term ‘eradicate’ with wording that reflects the reality of long-term management – these changes affecting one million sales per year.
Infrastructure adoption – the Welsh Government applied the research to 1,300 km of road assets, and Network Rail implemented it across 2,700km of track, achieving over 95% control within 2-3 years and significantly reducing long-term management costs and legal risks.
Judicial benchmark – the core research paper (Jones et al. 2018) is now a standard reference in civil courts to define the ‘measured duty of care’ required of landowners.
Economic benefit – by clarifying liability and enabling more informed lending decisions, the changes have helped more mortgage offers be approved for properties previously ‘blighted’ by Knotweed.
Summary
This academic impact project, submitted to the Research Excellence Framework (REF) 2021, details how the world’s largest field trial for Japanese Knotweed control revolutionised legal, economic, and infrastructure standards across the UK. By testing 19 different management methods over several years, the research team identified a definitive ‘Four-Stage Model’ for effective glyphosate application, filling a critical empirical gap that had previously led to the use of untested and expensive treatments. The study’s findings triggered a comprehensive overhaul of the UK legal system – including the Law Society’s update to the TA6 Property Information Form – and were adopted by major infrastructure operators like Network Rail and the Welsh Government to achieve over 95% control across thousands of kilometres of assets. Beyond operational success, the research established a new judicial benchmark for the ‘measured duty of care’ in civil courts and stabilised the national property market by providing lenders with the scientific certainty required to approve mortgages on previously ‘blighted’ properties.