BGCI is working with the University of Ghent Botanical Garden (Belgium) and the Instituto de Ecología, A.C. (Mexico) on an exciting project to assess the conservation status of Hydrangea species and develop an action plan for conservation of priority species.
The genus Hydrangea Linnaeus has more than 1,000 cultivars and hybrids already since for centuries it has been a very popular ornamental plant group. These ornamentals with inflorescences with attractive marginal flowers are commonly known as hortensias, and descend from Asian shrubby species such as H. macrophylla and H. aspera.
BGCI is working with the University of Ghent Botanical Garden and the Instituto de Ecologia, A.C. to assess the conservation status of Hydrangea species. Conservation assessments will be submitted to the IUCN Red List of Threatened Species and a Red List publication will produced.
In the course of our ongoing work for this Red List and for specific projects on conservation, evolution and taxonomy of this genus, recent expeditions have been organized to the following countries: Chile, China, Costa Rica, Ecuador, Japan, Mexico, Peru, and Taiwan, covering a substantial part of its distribution area in tropical and subtropical areas.
Many populations of Hydrangea in China, especially those at lower altitudes, seem to be in danger of being overrun by the development of roads and buildings. However, at these lower altitudes Hydrangea seems to thrive close to roads, which allow more sunlight into some of the denser woods, something which seems a necessity for flowering in these Hydrangea taxa. Higher up in the mountains the situation seems different. Populations are smaller and less dense for some taxa, while others remain somewhat abundant. Here the main threat seems to be tourism, as many of the higher mountains are holy places for Buddhism, with temples and hotels for visitors.
In Japan, the main issue seems to be introgression of cultivated plants into natural populations. Many parks and natural areas have been planted with cultivated forms of Hydrangea macrophylla, which sometimes makes it hard to distinguish between wild populations of this species and planted groups of plants.