Project background
The spread of invasive alien species (IAS) is widely recognized as one of the main drivers of biodiversity loss in Europe. Damage caused by the expansion of IAS can be significant and therefore requires the implementation of control actions aimed at reducing their population. The horticultural industry in Europe and elsewhere in the world has made a vast array of diverse plant species available to the public. In Europe, some 17 000 taxa (12 000 species plus subspecies, varieties and hybrids) are grown in gardens and new species are constantly sought. Some of these plants have proved to be invasive and to affect native biodiversity. In fact, ornamental horticulture is the main pathway of plant invasion worldwide. In Belgium, almost all black list plants have been introduced as ornamental plants. A survey conducted in 2006 showed that 25 out of the 28 black list species were present in horticultural catalogues. When informed about the risks of biodiversity loss caused by some commercialised species, nursery professionals were found to be responsive to the issue and concerned by the detrimental impacts of these IAS.

Project objectives
The overall objective of the InvHorti project is to reduce the introduction of invasive alien plants (IAPs) by raising awareness about the environmental risks among the whole ornamental horticulture supply chain in Belgium, from growers to gardeners. The project aims to promote best practices for preventing the release and spread of IAPs and to promote adherence to a Belgian voluntary code of conduct developed by the project on IAPs and horticulture.

It will target some 2500 ornamental horticulture professionals (including nurserymen, garden centre managers, wholesalers,  garden contractors, landscape architects and open spaces managers), as well as 100 horticulture teachers and 400,000 garden amateurs.

Three awareness campaigns will be carried out. The first will sensitise the target audiences to the IAPs issue and inform them of which IAPs are found in Belgium. The second will communicate best practice to prevent the release of IAPs, and will promote the Belgian code of conduct and the use of alternative plants. The third will specifically target hortiultural teachers. A wide range of channels and tools will be used, including press, TV, radio, information sessions, stands at horticultural fairs, brochures, folders, posters, DVD, etc. Key messages concern:

- Raising awareness on the environmental consequences of IAPs;
- Encouraging professionals to stop growing, retailing and recommending the use of IAPs to customers;
- Encouraging gardeners to stop planting IAPs and widely publicise harmless alternatives;
- Disseminating best practices in getting rid of IAP wastes and avoiding their unintentional introduction and spreading

At the end of the project it is expected that:

- at least 20% of the horticultural professionals and 60 % the public green space managers will have endorsed the voluntary codes of conduct, leading to a reduction by at least 20% of the use of invasive plants by professionals.
- IAP-related training will be organised on an annual basis by at least 50% of the horticultural schools in Belgium.      
- there will be an improved awareness of gardeners to IAPs, with at least 10 % aware of the code of conduct and knowing that invasive plants may be substituted by harmless alternative plants.

Project partners
CTH (Technical Centre for Horticulture), Belgium
PCS (Research Centre for Ornamental Plants), Belgium
SPF Environment (Federal Ministry of the Environment), Belgium