Be careful when mowing around dogwoods. As soon as possible after injuring the bark, paint the exposed wood with tree-wound dressing. Decay in the lower part of the trunk sometimes can be cut out. After removing all the decayed wood, sterilize the cavity by painting with shellac. Leaf and Flower Spots.
Several diseases can infect dogwood leaves and flowers and cause spotting and dying.
These diseases often mar the appearance of the tree and can cause defoliation at times. Usually they do no permanent harm to the tree. One disease that seriously disfigures flowers and leaves is called spot anthracnose. Apply the spray as the flowers open. For best control of leaf and flower diseases, spray every 3 or 4 weeks during spring and summer.