The breeding these azaleas began early on in Japan centuries before it was opened to western botanists. The Exbury Hybrids were developed by Baron von Rothschild at his Exbury, England estate. During the 1920s and 30s, he combined existing hybrids with those imported from North America, Japan and China to produce some truly astounding new plants. Exburys did not do well in the American South where so many other azaleas thrive due to a marked intolerance of extreme heat. However, Exburys have been used by southern breeders in the ancestry of modern hybrids due to the improvement in flower size and quantity.

Though they are known as azaleas, all azalea hybrids are technically members of the genus Rhododendron. Azaleas and cherry blossoms are the two plants that symbolize spring in the Japanese tea garden.