The heathers or heaths include both the small genera Calluna and Daboecia and the over 800 species of Erica. As Nelson and Pirie write, heathers have gone through phases of popularity in horticulture, including bursts of enthusiasm among gardeners both for Northern Hemisphere (hardy) heathers and the much greater diversity of Southern Hemisphere species. Two Cape Erica species, E. verticillata and E. turgida, survived in botanic gardens after going extinct in the wild. To quote the authors:
“Fertile cultivars of heath and heather species represent in part discoveries over decades of a range of morphological variation in wild populations […]. This variation may reflect an underlying, highly variable genomic diversity within species with origins dating back thousands or even millions of years. It certainly represents the long-term future of the horticultural trade and a contribution by gardens and gardeners towards preserving biological diversity into an uncertain future.”
Charles Nelson has authored numerous works on heathers, including in 2012 the Kew Monograph ‘Hardy Heathers from the Northern Hemisphere’. Michael Pirie coordinates the Global Conservation Consortium for Erica.
Their article is freely available (open access) at https://doi.org/10.24823/Sibbaldia.2022.1887.