Azaleas
 The spectacular spring flowers of azaleas make them among the most popular garden shrubs. Also, Azaleas have many landscape uses. Azaleas are shrubs for all seasons. Throughout the summer and fall, the leaves add a pleasing, deep-green color to the garden. Some deciduous azaleas, such as the Exbury Azalea, add bright fall color before the leaves drop.
Azaleas are classed as Rhododendron by plant taxonomists. The name "azalea" is commonly used for native deciduous species and many evergreen hybrid types. Generally "rhododendron" is used for those species that have large, evergreen, leathery leaves and flowers distinctly clustered in terminal groups. The culture required for all these plants is very similar. The same cultural practices may also be applied to blueberries, pieris, heather, holly, and other plants that prefer acid, organic soils.
 People tend to think of azaleas and rhododendrons as shade loving plants. However, dense shade is not the best situation for these plants. Filtered sunlight is ideal, but morning sunlight with shade after 1 p.m. is desirable in most climates. Plants may survive continuous shade if trees have branches pruned high. Fences, shrubbery, or screens may also give protection from afternoon sun.
Some deciduous azaleas will tolerate more sun, and should be used if the location receives full afternoon sun. However, in full sun the flower colors may not be as bright because of the intense light.
Both Azaleas and Rhododendrons must have an acid soil. Most of them thrive best at a soil pH between 4.5 and 6.0. If the pH is too high, the soil may be made more acid by applying agricultural sulfur or iron sulfate. The amount the pH will change varies with different soils, but generally about one and one-fourth cups of iron sulfate or two and one-half pounds of agricultural sulfur per 100 square feet will lower the pH one unit. Also, soils that are too acid (below pH 4.5) may easily be made less acid by adding ground limestone.
There is little need for pruning azaleas and rhododendrons. If growth becomes excessive, reduce the size with light pruning. It is important to remove the flower stems on Azaleas as soon as flowering is complete, and for sure within six weeks of flowering. If you prune after this period, the plant will not flower the following year
There are several insects and diseases that commonly bother azaleas. The most common insect problem is the azalea lacebug, but also aphids, leaf miners and tiers, and scale can be a problem.
The most common diseases on azaleas are Phytophthora root and crown rot and Ovulinia petal blight. In addition to these, rhododendrons can also be bothered by Botryosphaeria canker and dieback.
|
