Shrub Diseases

Shrubs and bushes provide attractive additions to many landscape designs. These medium-sized plants create borders when used as hedges. Due to their smaller growth, shrubs fill in areas in landscapes too small for large trees. When healthy, shrubs add to the beauty and function of the yard. Unfortunately, many shrubs suffer from various types of diseases. Some diseases mainly affect certain types of shrubs. These unhealthy conditions exhibit a variety of symptoms in landscape shrubs and bushes.

Leaf Spot Disease

Leaf spot disease actually encompasses a variety of conditions. Most types of leaf spot disease occur when pathogenic fungi attack the shrub. This fungus creates the appearance of black and brown blotches on the leaves of healthy shrubs. Spreading spores affect large segments of some shrubs. Cool humid temperatures create a favorable climate for the spread of leaf spot disease. Diseased bushes shed dead leaves, exposing sparse and bare branches. Some cases of leaf spot disease disappear when the humidity decreases and the temperatures warm up. Applications of fungicide destroy leaf spot disease and encourage healthy, new growth. Repeated applications during rainy periods ensure the best chances of successful treatment of this disease in shrubs.

Sooty Mold

Like other types of fungus, sooty mold affects shrubs in areas of high humidity. Sooty mold creates a dark brown coating on the surface of leaves and stems. Rubbing these affected areas removes the moldy coating. This condition attacks shrubs damaged by aphids and other insects. The mildew adheres to the damaged areas that secrete plant juices from openings caused by feeding insects. The use of insecticide spray reduces the initial damage to the shrubs, eliminating the occurrence of subsequent mildew caused by sooty mold.

Root Rot

Various types of root rot affect many evergreen and deciduous shrubs. Caused by over-watering or poor drainage, root rot damages the roots of shrubs and bushes. Shrubs suffering from root rot appear wilted. Excessive loss of leaves from shrubs grown in soggy soil indicates the presence of this condition. Preventative measures often eliminate the occurrence of root rot. Planting shrubs in landscape locations that provide adequate drainage eliminates many types of root rot. Adding sand and compost to heavy, clay soils increases the porosity of the soil, allowing water to drain away from the roots.

Keywords: shrub diseases, shrub condition, mildew on shrubs

About this Author

Piper Li, a professional freelance writer, began writing in 1989. Her articles appear in Modern Mom, Biz Mojo, Walden University and GardenGuides. She is the co-editor for "Kansas Women: Focus on Health." With a bachelor's degree in journalism from Mesa State, Li enjoys writing about health, horticulture and business management.