| Like all evergreen plants, evergreen azaleas periodically lose some of their foliage, and the leaves may turn yellow, red, or purple before they fall. Often the only leaves that remain are those that surround the flower buds at the tips of the branches. This characteristic is linked to the genetics of the parents used to breed garden azaleas. The degree of leaf coloration or loss is a function of parentage and not the severity of the winter. In unusually cold winters, certain azaleas may lose more leaves than they would in mild winters. All of the evergreen azaleas are native to Asia. They appear to be evergreen because they grow two sets of leaves each year. Evergreen azaleas have dimorphic leaves, known as spring leaves and summer leaves. The spring leaves unfold at the beginning of the growing season and are dropped in autumn. Summer leaves emerge in early summer and are smaller, thicker, darker, and more leathery than spring leaves. They remain on the plant during the dormant period and drop in the spring, however, summer leaves may persist for several years in warm climates. Some "evergreen" azaleas are deciduous in colder climates. Sometimes this is called being semievergreen. |
Here is a link that might be useful: How to care for rhododendrons and azaleas.
