Azaleas are a popular addition to any garden or landscape, for their beauty and easy maintenance once established. However, although they are generally healthy plants, they are subject to a variety of problems, whether it is disease, pests, or nutritional deficiencies. These problems can usually be controlled with proper care and materials, but it is important to first be able to recognize the problems and what is causing them.
The most common flower problems is petal blight, where the flowers appear spotted, then wilt and become slimy within a couple of days. The petals then turn brown and cling to the stem of the azalea. This disease is more severe in cool, moist springs and is caused by an airborne fungus.
Azalea lacebug is another azalea pest that causes a common leaf problem where the top of the leaves appears blanched, gray, or spotted. The underside of the leaves also becomes discolored from what the lacebug produces. Certain pesticides can get rid of the lacebug.
Chlorosis is a problem where the leaves turn quickly from light green to yellow, then finally to a cream color although the leaf veins remain green. Chlorosis is usually caused by the soil pH being too high, making iron unavailable to plants. This can be fixed easily by altering the soil.
Foliar feeders consist of a variety of insects that feed on the leaves, creating holes and ragged edges. And leaf gall is a disease where the leaves curl up; this happens most often in cool, moist weather. Leaf spots are easily identified by browning leaves with tiny, black fruiting bodies or discolored spots.
Nematodes are a very common yet serious problem for azalea plants, where the leaves turn yellow and the entire plant stops growing. No chemical remedy is available. Scale insects are found on the twigs or branches of the azalea, in various colors and sizes. A pesticide can be used to get rid of these. Winter injury on an azalea is where the entire plant or branches die off in the growing season. This could happen because your azalea is not a cold-hardy variety, and you are using too much fertilizer or water during the winter season.