Tomos Jones1, Alastair Culham1, Brian Pickles1 and John David2
1School of Biological Sciences, University of Reading, Whiteknights Campus, Reading, UK
2Royal Horticultural Society, UK
The Royal Horticultural Society’s (RHS) Plant Finder (Cubey 2019) contains over 78,000 entries including 17,000 different species. This compares to a native flora of only 1,500 in Britain and Ireland. Most of these ornamental plants have not ‘escaped the garden fence’ and naturalized, and even fewer have become invasive (Fig.1). However, some currently well behaved ornamental plants have the potential to naturalise and/or become invasive in the future as a result of a changing climate (Webster et al. 2017). This project adopts an interdisciplinary approach to investigate the impact of climate change on this invasive potential.
Ornamental plants can show characteristics typical of invasive species and gardeners can be the first to observe plants showing invasive characteristics within gardens. For this reason, an online survey asked gardeners in Britain and Ireland to report ornamental plants taking over or invading their gardens. Over 500 gardeners completed the survey, reporting over 150 different ornamental plants at different stages of the naturalization-invasion process. Plants from this survey have been chosen for an exhibit called Ornamental plants: our future invaders? in the Discovery Zone at the RHS Chelsea Flower Show (May 21– 25). At Chelsea, a survey will also ask gardeners to report problematic species growing in their gardens and collect information on how they try to manage or eradicate these plants. Chelsea attracts over 166,800 visitors every year and this will be an important opportunity to promote this citizen science project. The Chelsea survey will also be available online for gardeners who have not visited the Show, which will widen the demographic and geographic scope represented by survey respondents.
The ornamental plants reported by gardeners in such a way will not necessarily become invasive in the wider environment. Therefore, these plants are being investigated further using species distribution modelling (SDM) to indicate which ones might find future climates suitable. Results from the survey at Chelsea, along with the SDM, will be presented. It is important to identify which ornamental plants have naturalization or invasive potential before they become problematic. This interdisciplinary approach has the potential to identify problematic plants early in the naturalization-invasion process.
Cubey J. (2019) RHS Plant Finder 2019. RHS, London.
Stace C. A. & Crawley M. J. (2015) Alien plants. HarperCollins Publishers, London.
Webster E., Cameron R. & Culham A. (2017) Gardening in a changing climate. RHS, Wisley.