Plant Health Alliance


It is recognised that the movement of live plants is a high-risk pathway for the introduction of potentially damaging notifiable plant pests (and diseases) into new areas. By far the greatest volume of live plant movement is by the trade. Several recent plant pest introductions (e.g. ramorum disease, box moth, ash dieback and oak processionary moth) and industry concerns about the risks posed by Xylella led to focused efforts on improving plant health management across different sectors and along their supply chains. Industry, environmental NGOs and Government worked together to develop the Plant Health Management Standard (PHMS), published in 2019, and the associated Plant Healthy Certification Scheme, which was launched to the sector in February 2020.


Integral to this initiative, and chaired by Sir Nicholas Bacon, was the formation of the Plant Health Alliance; a group of professionals from ornamental horticulture, forestry, and general land management backgrounds, as well trade bodies, environmental NGOs and Government. Defra is represented by the UK Chief Plant Health Officer. The Alliance owns the PHMS (current version 1.2). The PHMS is referenced in the Plant Biosecurity Strategy for Great Britain (2023-2028) and is held and continually developed in the spirit of shared responsibility. The PHMS is publicly and freely available to everybody with a view to support all people protect our cultivated and natural landscapes.


Plant Health Management Standard (PHMS)


Defra and the Plant Health Seed Inspectorate support the development of the PHMS by providing funding and technical expertise. The PHMS takes a proactive or systems approach to plant biosecurity and sets out 31 requirements all aimed at protecting plant health. It aims to enable managers to demonstrate that the sites and the associated operations they are responsible for operate in a biosecure manner. The PHMS aligns with and builds upon the regulatory framework and as such it is co-designed in partnership between regulators and practitioners.


The Standard is broken down into different areas and covers whole plant cultivation and movement processes – from sourcing and supplying plants to ongoing site management and husbandry. Two key concepts are integral to the PHMS: World Trade Organisation's Appropriate Level of Protection; and International Plant Protection Convention’s Pest Risk Analysis. These concepts have been adapted to be applicable to individual horticultural sites. The PHMS enables professional plants people to take responsibility for plant health by periodically conducting a systematic analysis of the critical points of their site and operations. This can be summarised as follows:



There is an ongoing requirement to have in place a monitoring regime and self-assessment process, all with a view to the development and continual improvement of robust pest risk management systems.


Plant Healthy Certification


The Plant Health Alliance is the Governing Body for the Plant Healthy Certification Scheme. The Scheme aims to help organisations grow, supply and handle plants responsibly and safely, regardless of whether the plants are imported or grown in the UK, or a mix of both.


Professional plants people can find out how ‘Plant Healthy-ready’ they are by completing a free online self-assessment on the Plant Healthy website. Also, on this website are Five e-learning modules designed to help organisations build their knowledge of the principles of plant biosecurity and the regulatory framework. The freely available modules incorporate an end assessment of 20 questions with a pass rate of 80% required to obtain a certificate.


Once ready for Plant Healthy certification, an organisation can apply to one of the Scheme’s Certification Bodies who will carry out an independent audit of both paperwork and the applicant’s site(s) against the PHMS. There is a cost to become certified. The fees were developed on a sliding scale – the larger the turnover of a business, the higher the fee. The two not-for-profit Certification Bodies charge a separate fee to cover administration costs, expenses and time for an auditor to visit a site. It is recognised that some may find the scheme too costly and the Plant Health Alliance are working to develop robust auditing systems for smaller businesses and community groups. 


Once the business or organisation has passed the audit, it is entitled to use the Plant Healthy logo and branding to show that they are Plant Healthy Certified. A directory of certified members is on the Plant Healthy website.


The scheme covers: plant nurseries, retailers, landscapers, arborists and public gardens. Over forty horticultural businesses as well as RHS Harlow Carr, RBG Edinburgh and RBG Kew are now certified.


An emerging threat


Many professionals within the sector are striving to minimise the threat from new plant pests and diseases being introduced and spread in the UK. Equally, Government are attempting to work with the trade to establish a regime of fit for purpose plant movement checks. This is a huge challenge given the volume and diversity of plant material that is moved and the range of different plants pests that have been identified so far (there are currently 1,407 pests on the UK Plant Health Risk Register). The fact is that recently there has been a considerable increase in the occurrence of new plant pests and diseases in GB. The graph below that is sourced from the Forestry Commission, shows some examples of tree pests that have arrived into GB in recent decades. The increase in plant pest occurrences mirrors an increase over the last 10 to 15 Years in the global trade in plants and plant products.  



A single standard - linking effective regulation with responsible trade


As identified in the House of Lords Paper 191 (European Union Committee Brexit: plant and animal biosecurity), cooperation is essential. Society must actively seek to understand the extent of this evolving threat and work together to develop effective measures to protect our cultivated and natural landscapes. The central aim of the Plant Health Alliance is to foster a partnership approach between all relevant organisations to continually seek evidence-based approaches to counter the movement and spread of all notifiable plant pests. Effective research programmes should inform areas where the PHMS can be improved with the Standard subsequently incorporating new knowledge through a process of standard setting. This continual improvement process enables Government and the sector to adopt the latest version of the Standard to enhance their respective, yet linked, biosecurity systems.


Appended to the Terms of Reference of the Plant Health Alliance is a document entitled ‘A basis for working together’. The approach is straightforward - a single Standard is continually developed by consensus and used as a basis to enhance biosecurity practice to minimise the threats from the movement of live plants and plant material. The design of multiple processes that work in sequence to halt plant pest spread is known as a ‘systems approach’. The Standard encapsulates both regulatory and voluntary measures with a view to enable those who are best placed to implement biosecurity practices and checks. Progress has been made in recent times, however a concern is that alternative Government or voluntary standards are developed leading to confusion and fragmentation. We therefore urge all public and private bodies to work in partnership to contribute to the co-owned PHMS and to use it as a central reference point in the development of new regulations, policies or voluntary assurance schemes.




14 July 2023