My Encore Azaleas Look Like They Have a Disease

Root Rot

• An Encore azalea that wilts suddenly, has yellowing leaves and displays discoloration on the trunk near the stem’s base is likely suffering from root rot or crown rot. Azaleas suffering from root rot also slowly develop new growth in the spring. This disease commonly affects azalea plants during wet weather and damp growing conditions. The fungus Phytophthora causes the disease . Planting Encore azaleas in a spot with good drainage or in a raised bed prevents root rot disease.

Disease Symptoms on Petals

• Azaleas, including Encore hybrids, can suffer petal blight. Petal blight is caused by a fungus called Ovulinia azaleae. Look for white- or rust-colored spots on the flowers. As the disease advances, the fungal spots spread, causing the petals to rot and fall. The disease shows up most often in damp weather and towards the end of the growing season. Remove fallen flowers from the ground, clip affected flowers from the bush and discard them.

Symptoms of Leaves

• Leaf spot is a nonserious disease that causes spots on leaves. This fungal disease often goes away without treatment. Avoiding getting the leaves wet when watering helps prevent leaf spot from developing and spreading. Leaf gall is another nonserious disease that causes the leaves to turn white or pale green. This disease shows up most often in the spring and goes away on its own. Azaleas that develop rust-colored spots on the underside of the leaves are likely suffering from leaf rust. Rake up the dead leaves in fall to prevent the fungus from overwintering on the ground.

Twig Blight

• An Encore azalea that wilts suddenly and starts losing leaves may be suffering from twig blight. Peel back a small section of the bark to check for this disease. The wood under healthy azaleas should be white or pale green. Azaleas suffering from twig blight have rust- or brown-colored wood under the bark. Remove all affected the branches with pruning shears. Disinfecting the tools between each cut prevents the disease from spreading.