19. American Azaleas
Cultivars of North American Rhododendron species.
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In the United States there are 15 wild species of deciduous rhododendrons (azaleas). Only one, Rhododendron occidentale, is known from the Pacific Coast, but it happens to have the largest flowers, and it is scented. It is particularly valuable in breeding due to its late flowering and its use has resulted in an extended flowering-season for garden azaleas. The best known of these crosses is ‘Irene Koster’ which dates back to around 1900. However, there is a renewed interest in the States in using this species, and new cultivars are continuously being launched.
Several of the other American species have also been used in breeding from early on, resulting in the Ghent azaleas (across the road). A very special breed has come from the strongly scented, small- and late flowered Rhododendron viscosum. Most flower in shades of pastel, as in ‘Soir de Paris’. They have a distinctive, elegant appearance, which is overshadowed if placed with brasher, larger-flowered cultivars.
