Root & Crown Rot of Azalea

Disease Information

Root & Crown Rot

Symptoms and damage

The fungus Phytophthora species causes one of the most common disease problems in the landscape for rhododendron and azalea. This fungus is a "water mold," and thrives in poorly drained or wet conditions. A wilted plant is usually the first sign of trouble. Rhododendron leaves will curl inward and droop. Drought can cause similar symptoms. Roots of affected plants appear soggy or blackened, and the outer portion of the root easily pulls away from the inner portion.Crownrot causes the lower portions of the stem to have a brown discoloration of the wood near the soil line.


 Prevention of disease is important, because chemical controls are ineffective once symptoms appear in the landscape. Begin by purchasing disease-free plants from a reputable nursery. Avoid plants that lack normal green color, appear wilted in the morning, or have dark, discolored roots. Select resistant varieties for planting .

Plant azaleas and rhododendrons in a well-drained and well-aerated soil. Heavier clay soils should be amended with organic matter before planting. Avoid planting in areas where water can collect around plant roots.


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