Holly bushes are highly colorful and highly tolerant to many climates and conditions. This ornamental bush can become infected with various diseases like any other type of ornamental plant. One of the most susceptible parts of the holly bush are the leaves. There are five common holly bush leaf diseases which can strike during different times of the year. Proper planting and maintenance can greatly reduce the chance of holly bush leaf diseases from occurring.
Holly bush leaves can suffer from various diseases. The most common are Honey Dew Fungi, Tar Spot, Spine Spot, Bot Canker and Iron Chlorosis. Honey Dew Fungi grows in humid soil; this disease makes the leaves wilt and fall off. Toadstools will begin to form around the base of affected bushes. Tar Spot is a fungal disease that thrives in cooler seasons; this disease causes yellow spots on leaves eventually turning them brown then black. Spine Spot is evident by signs of small gray spots with purple margins. Signs of Bot Cankers include sunken lesions on stems and brown decay under loose bark; branches will begin to die when left untreated.
The most common cause of holly bush leaf diseases is fungal infections. Mold is another cause; this is brought about by aphid excrement left behind after they feed on the sap of the holly bush. Poor soil conditions, such as high pH levels or poor iron content are another cause of holly bush leaf disease.
Certain holly bush leaf diseases can be fatal if left unattended. Diseases caused by fungus are usually the reason infected holly bushes wither and die out. Infected bushes can infect other nearby bushes, especially those in close proximity. Moving uninfected bushes can help reduce this effect. The effects of holly bush leaf diseases can become apparent within one season.
Leaves affected by Tar Spot and Bot Canker must be destroyed away from surviving plants to avoid further infection of the holly bush. Removal of aphids from holly bushes will help eliminate the chance of Sooty Mold. Introducing ladybugs into the area will help control the aphid population. Pruning off affected branches also helps to reduce the chance of holly bush leaf diseases spreading. Mold can be removed by spraying the holly leaves with water from a garden hose. Use of a light soap can remove hard-to-clean spots. Setting up wind breaks around the holly bushes will help eliminate the chance of wind problems where leaves can puncture adjacent leaves causing Spine Spot.
Planting holly bushes in suitable locations helps reduce the chance of initial infection. Setting bushes far enough apart so the leaves do not touch can greatly reduce the chance of fungi spreading as well as an outbreak of Spine Spot. This also helps in providing room for pruning and other yearly maintenance. Using fungicide can help prevent infected holly bushes from infecting other bushes. Maintaining low levels of pH can avoid an outbreak of Iron Chlorosis; planting holly bushes away from concrete areas can help prevent this disease. Proper fertilization of the ground will also help prevent outbreaks.