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Horticulture PAP for Great Britain

Pre-consultation version, drafted September 2022.  Download a PDF version of this plan. This Pathway Action Plan was drafted by a working group, the membership of which is listed at Annex 1

Background to action planning

Reducing the risk posed by pathways of introduction and spread is a key way of tackling invasive non-native species (INNS).  The GB INNS Strategy calls for the development of Pathway Action Plans (PAPs) which are also a requirement under the IAS Regulation.    

This Pathway Action Plan is one of a series of plans intended to address pathways of introduction or spread of non-native species in Great Britain.  The plan outlines the general policy and approaches as well as deliverables by the horticulture industry, government and consumers in relation to this issue.   


This plan is aimed at the horticulture pathway, covering invasive non-native plant species (including trees) in all environments: terrestrial, freshwater and marine.  It includes professionals involved in the horticulture sector as well as gardeners and other end-users. The PAP also covers invasive species that hitch-hike on plants (or on/in media such as pots or soil associated with the plants).  The PAP will not cover species that are already covered by the Plant Health regime but will cover species that are not injurious to plants such as ants and flatworms.  Microorganisms are out of scope but hitchhiking macro-fungi are within scope where they fall outside of the scope of Plant Health.  The geographical scope of the PAP is GB but it will also make reference where relevant to Northern Ireland and other members of the British–Irish Council.

This plan was prepared by a working group (the GB Horticulture PAP Working Group) reporting to the UK Non-native Species Programme Board (see Annex 1 for membership).  A sub-group on horticultural hitchhikers oversaw these parts of the PAP.


There are currently around 2,000 non-native species established in the wild in GB and an additional 12 species become established annually.  Around 70% of these species are plants and most of those have been introduced via the horticulture trade.  In addition, numerous species have been introduced as hitchhikers associated with horticulture.  Fortunately, while the horticulture trade is responsible for the introduction of more species than any other pathway, most of these species (particularly terrestrial plants) do not go on to cause us problems.  Despite this, of the approximately 200 non-native species that have known negative impacts, 40% are likely to have been introduced by this pathway.  It is therefore critical that we address the horticulture pathway by developing and implementing a horticultural pathway action plan.

We anticipate that climate change will increase the range and abundance of many of the invasive ornamental plants currently damaging our environment. We also anticipate that some currently benign ornamental plants in gardens and ponds will become invasive due to the changing climate. It is therefore crucial that we manage the risk that this pathway represents effectively.

A survey of public attitudes in 2018 found that over 80% of the general public possessed a garden and one in six had a pond/water feature.  Plants were mainly sourced from: garden centres, DIY stores, supermarkets and nurseries/friends.  Just under 1% (which represents a large number of people) admitted to disposing of plants  in the wild and only 7% had heard of Be Plant Wise [1].  The main sources of information used by gardeners were plant labels, seed packets, friends, garden centre staff and the internet (in descending order).

There are Horticulture codes of practice for England and Wales (2005, updated 2011) and a separate one for Scotland (2005) and a European code that was developed under the Bern Convention but these appear to have had limited impact to date.  This area is also covered by a number of relevant Acts in domestic legislation.  The Wildlife and Countryside Act (1981) provides a general prohibition on the release of most non-native species of animal throughout Great Britain.  In England and Wales, some 55 plants are listed on Schedule 9 of the 1981 Act which may not be planted or allowed to spread into the wild.  Other provisions of the 1981 Act allow for the prohibition of sale, although currently only three aquatic plant species are banned from sale in England under this legislation.  In addition, the IAS Regulation has a list of species, which are banned from import, sale, keeping, growing or cultivation, and release etc.  There are currently 36 plant species listed under this regulation and one hitchhiker species (the New Zealand flatworm). In Scotland, there is a general prohibition on planting non-native plants in the wild and ‘white-list’ of non-native trees and wildflowers, which may be planted in the wild.  In Scotland the IAS Regulation has been implemented though amendments to the 1981 Act, with separate lists of species banned from sale and keeping. Northern Ireland is outside the scope of this PAP, but it is noted that Northern Ireland has a different list of regulated species. 

However, legislation alone is insufficient to manage and lower the risk associated with introducing or spreading of INNS.  It requires cooperation and collaboration from all concerned, each sector is part of the solution and plays an important role in INNS prevention. This plan sets out additional actions to help minimise the risk posed by non-native species associated with the horticulture trade. 

Its primary output has been to agree a series of measures to protect the environment from the introduction of plants and associated hitchhikers that are, or may become, invasive.  These actions are outlined below and they form the main body of the action plan.

Aims and objectives

The overall aim of the PAP is to reduce the risk of introduction and spread into the wild of invasive non-native plant species and invasive non-native species that hitchhike on plants (or on media such as soil associated with the plants). 

Specific objectives are to:

Invasive plants

1. Ensure that banned species are not being sold/exchanged by all routes including online.

2. Identify and remove the most invasive plant species or varieties from trade.

3. Ensure that all invasive or potentially invasive plants are correctly labelled using accepted/standard species and variety names.

4. Raise awareness of the issue of invasive non-native plants amongst key target audiences in the supply chain including importers, retailers and growers.

5. Raise awareness of invasive non-native species amongst gardeners, pond and aquarium owners in order to minimise the risk of plants getting into the wild.

Horticultural hitchhikers

6. Minimise the risk of contamination of horticulture plants and associated horticultural products entering GB.

7. Ensure there is seamless integration between the plant health regime and the pilot NNS Inspectorate – including sharing detection notifications for non-plant health pests.

8. Ensure that importers, nurseries and retailers know what to do if stock contaminated with invasive species is identified.

9. Raise awareness among gardeners and other key target audiences in relation to hitchhikers.


Action 1

INNS Inspectorate, working with PHSI as appropriate, to proactively attempt to detect the sale of banned species (including via online), respond to reports from other plant suppliers and to take forward suitable enforcement action.

Action 2

Defra, Scottish, Welsh Government, RHS and HTA will work together to raise awareness of the sector (retailers and producers mainly) about listed species, as well as providing guidance on the planting and disposal of unlisted invasive species.

Action 3

Government will propose further species for listing as species of special concern.  All proposals will be prioritised before being put forward for risk assessment and consultation and final ministerial agreement.

Action 4

Defra, Scottish and Welsh Governments to work with the industry and other relevant stakeholders to identify plants that have the potential to become invasive, including those affected by  our changing climate and ensure that our regulatory approach is adequate to protect our environment from them. This will take into consideration horizon scanning, which should be adapted to take better account of species that are already established in GB.

Action 4A

Horticulture industry, trades bodies, RHS and other relevant stakeholders to facilitate collation of evidence of invasive behaviour of ornamental plants, use this information as to advise consumers and share this with government bodies.

Action 4B

A reporting mechanism to be put in place for reporting ornamental plants that display invasive behaviour (e.g. via Plant Alert).

Action 5

NNS Inspectorate to work with the RHS to develop of a list of commonly used incorrect names of plants used accidentally or deliberately to avoid regulation which could be used to screen imports into and movements within GB. 

Action 5a 

All to use the Kew Plants of the World database as the principal taxonomic authority (note that other sources, e.g. RHS and Standard British Flora (Stace ed 4) are valuable and may use different taxonomy).

Action 6

Defra, Scottish and Welsh Governments to develop proposals for a labelling system (of words and/or symbols) to warn gardeners that certain plants may be invasive in certain circumstances and advice on safe disposal.  

Action 7

NNSS and Governments to sustain and promote Be Plant Wise and update it as necessary and to facilitate the dissemination of the ‘alternatives booklets’

Action 8

The Horticulture Sector and Plant Network to encourage their members to assist with awareness raising of invasive non-native plants, including by promoting Be Plant Wise and the alternatives booklets. As part of awareness raising activities, if listed species are detected in trade they should be reported to nnsi@apha.gov.uk.

Action 9

The NNS Training Working Group to work with the horticulture sector working and training providers (e.g. BASIS) to identify key training for importers, retailers and growers.

Action 10

NNSS to work with NNSIP and the NNS Inspectorate to identify the key risks (species and commodities) related to horticultural hitchhikers – using existing horizon scanning lists and data on interceptions.

Action 11

The NNS Inspectorate, working with PHSI, to proactively attempt to detect invasive non-native hitchhikers on and in horticulture-related imports using a risk-based approach and to take forward suitable regulatory and enforcement action.

Action 11a

PHSI and Plant Health colleagues to facilitate the detection of hitchhikers by: i. working with the INNS inspectorate to raise awareness among PHSI inspectors; and, ii. sharing reports of relevant non-plant health pests with the INNS inspectorate in a timely manner.

Action 12

Government will propose further priority hitchhiker taxa for listing as IAS of Special Concern to ensure relevant provisions of the IAS legislation are in place.

Action 13

Defra, Scottish and Welsh Governments to assess gaps in legislation (e.g. powers at the border) related to horticultural hitchhikers and seek to plug these as legislative opportunities arise.

Action 14

INNS Inspectorate and PHSI to raise awareness within the industry so they know what to do if a consignment is found to be contaminated with priority hitchhiker taxa.

Action 15

The INNS Inspectorate, building on existing mechanisms, to establish a reporting route/mechanism for consumers and the sector to report the occurrence of relevant hitch-hiker species.

Action 16

Plant Healthy to seek to include a requirement on horticultural hitchhikers when the Plant Health Management Standard is updated.

Action 17

NNSS (with RHS) to explore the development of user-friendly guidance for gardeners on how to avoid picking up and spreading hitchhikers and what to do if you find them (including exploration of the overlap with the Don’t Risk It campaign run by Plant Health).

Action 17a

A task-and-finish group will be established to review existing guidance and develop new guidance on flatworms as well as develop new guidance on ants.

Monitoring and updating

The working group will be re-convened at least annually to assess progress with achieving the actions. 

For assessing overall progress with delivery of the PAP the group will consider all relevant information including the following:

  • Changes in the level of awareness of those involved in the horticulture sector as assessed by the public attitudes survey.
  • Numbers of businesses selling banned species as measured by the Non-native Species Inspectorate (and other sources where relevant).
  • Numbers of contaminants detected via the NNSI, PHSI or reported by the sector.
  • Uptake of labelling (if developed).
  • Proportion of plant species in the trade that are assessed for their potential risk of becoming invasive.

Ultimately the horticulture PAP should help to reduce the number of new invasive non-native horticultural plants and contaminants establishing and spreading in the wild.  High level indicators, such as the JNCC B6 indicator and Defra’s ‘abatement’ indicator will be considered to try to assess this; however, it may be difficult to detect the specific impact of the horticulture PAP at this level.

Annex 1:  Working Group members

The following organisations were represented on the Horticulture PAP working group:

Environment Agency (Chair), Trevor Renals

NNSS (Secretary), Niall Moore/Olaf Booy

RHS, John David   

Buglife, Craig Macadam

OATA, Tracey King

Horticultural Trades Association, Pippa Greenwood

Landscape Institute, Harry Watkins

Defra NNS Policy, Sarah Webster/Olivia Euesden

Defra Plant Health, Sharon Matthews-Berry

PHSI, Kelvin Hughes

Plantlife Scotland, Alastair Whyte

Botanical Society of the British Isles, Kevin Walker

Woodland Trust, Matt Elliot

Scottish Government, Alasdair Thomson

Welsh Government, Claire Lawson/Tom Warren

Northern Irish Government, Rose Muir

Natural Resources Wales, Jennie Jones

Natural England, Gavin Measures 

Scottish Natural Heritage, Stan Whitaker/Jenny Park

SEPA, Jo Long

SASA, Jon Pickup

Kew, Sara Redstone

RGBE, David Knott/Katy Hayden

Coventry University, Katharina Dehnen-Schmutz

Hon. Curator (Plants), Linnean Society of London, Mark Spencer

Corresponding members:

DAERA – Northern Ireland