Originally, when plants were being classified by Linnaeus in the eighteenth century, azaleas were treated as a separate genus, because at that time only deciduous species were known in Europe. Later, however, when evergreen species were introduced, botanists decided that ail azaleas should be classified under the genus Rhododendron, It ts to be understood, then, that when a nurseryman or gardener talks about Azalea timsii botanically speaking he is referring to Rhododendron simsii.
The fact that nurserymen and gardeners in general have continued to call these plants azaleas means you will usually find that most plant catalogues list azaleas separately from rhododendrons. To avoid any confusion, all the plants included in this chapter are described as azaleas in accordance with general usage.
There are about 70 species of azaleas and, in classifying these, advantage has been taken of a natural division, many of the spccies being deciduous whereas others appear to be evergreens because they retain some of their leaves throughout the year. For pot culture we are only concerned with the evergreen species and hybrids.
The first evergreen azalea to be introduced into England was apparently the Indian azalea A. indica
(or indicum) which was sent from China in 1808, and at that time was erroneously thought to be of Chinese origin, but actually it originates from Japan. This spccies was known in Holland as early as 1680 but was lost to cultivation for a long period of time, in fact
until 1768 when a batch was imported from Batavia. It was because this species was shipped from the East Indies that it was named Azalea indica, and by the time it was discovered that it was of Japanese origin the misnomer had become established, so today it is still called A. indica or indicum.
During the first half of the nineteenth century only a small number of evergreen azaleas reached Great Britain, but it was a very different picture during the second halfof the century. This change was brought about by the many great plant-hunting expeditions which were organised during this period. In 1850 Joseph Hooker went collecting in the Eastern Himalayas and in 1855 Robert Fortune went to China. In 1899 Ernest Henry Wilson went to Western China and in later years to Japan.
All the evergreen azalea species originate in Eastern
Asia, mainly in Japan, China and Korea. The Japanese, in particular, have been cultivating azaleas lor over 300 years; consequently most of the plants sent to England by the plant collectors were azalea hybrids.
During the second half of the nineteenth century evergreen azaleas were arriving in Britain, Belgium, Holland, France and Germany in ever-increasing numbers. Nurserymen and enthusiastic amateurs were engaged in cross-breeding hybrids and species on a large scale. By the end of the century there were over 1,000 named varieties of Belgian Indian azaleas, just one group of azaleas, which is an illustration of the extent of the breeding activities at this time.
There are some 40 species of evergreen azaleas, of which only about one third have been used in the raising of all the many thousands of different hybrids which have been grown.
Evergreen azalea hybrids are divided into groups, of which there are four of particular interest, these being Belgian Indian Azaleas, Kurume Azaleas, Kaerapferi Azaleas and Glenn Dale Azaleas.
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