White dogwood trees are attractive spring-blooming plants that grow across the United States. Covering themselves with waxy white blooms, white dogwoods turn over to dark green foliage after the spring blooming cycle is complete. Commonly growing in zones 5-8, white dogwood trees are drought-tolerant, medium sized trees, reaching an adult height of 20 to 30 feet. Although these hardy trees are able to grow well in many different soil types and environments, much like other trees, they are susceptible to some diseases.
Inspect the tree for any physical damage. When all bark of the white dogwood tree is intact, you can rule out physical injuries that cause illness.
Examine the white dogwood for dead or blacking spots on the bark. This can be a sign of canker disease. Place a 5- to 6- inch layer of mulch around the base of the tree to relieve the tree of cankers around the base. The cause of cankers on other areas of the tree is unknown so a treatment is not available.
Look to see if there is any purple or tan spotting or darkening of the leaves. This can be a sign of fungal diseases such as leaf-spotting and anthracnose disease. Treat any fungal diseases with a fungicide.
Prune away any diseased portions of the dogwood tree using sharp pruning shears. Make your cut where the diseased limb joins the main branch or trunk of the tree. Larger branches may require garden loppers for easiest removal. Clean your pruning tools with rubbing alcohol between each cut to prevent spreading the disease to other areas of the tree.
Examine the lower extremities of the dogwood tree for signs of insect infestations. Common insects that feast on dogwood trees are boring insects. Look for a sandy, red material. This is the excrement of the boring insects. Tree any insect infestation with an insecticide.