Signs of Stress in Dogwood Trees
Flowering dogwoods provide both shade and an ornamental quality to the home landscape. They bloom profusely in spring, with white and sometime pink flower adoring the branches. Dogwoods grow best with some shade and moist soil. Looking for signs of stress in your flowering dogwoods enables you to remedy problems before they become severe and result in permanent damage or death of the tree.
Red, yellow or brown spots on the leaves is a symptom of tree stress. Leaves may begin dropping or wilting. Fungus on the leaves may cause the discoloration, or it may be indicative of overly moist conditions in the foliage. Leaves eventually die as more of the tree becomes affected if the cause isn't treated.
Dogwood flowers are actually modified leaf structures called bracts. When the tree is under stress the bracts may develop brown spots and a wrinkled appearance. Wet or humid conditions during flowering is commonly the cause of this stress. Powdery mildew, a grayish-white fungus growth, may also be visible on the affected bracts.
Crown die-back is indicative of dogwood borer infestation. The foliage near the top of the tree begins browning and stops producing new buds and leaves. Bark may also be missing or flaking off where the affected branches join the main trunk of the dogwood tree. As the crown continues to die, branches easily crack and break from wind or their own weight.
Cracking or peeling bark may indicate stress from a variety of factors. Peeling bark on the trunk or near the base of branches is usually caused by borer infestation. Bark damage or cuts near the base of the trunk are often caused by lawn equipment damage, such as from lawn mowers or string trimmer hitting the trunk. This damage may lead to further stress factors as the exposed trunk is prone to insect infestation.
Lower branch death is visible as the lower branches in the tree stop producing new leaf buds and begin dieing and drying out. New shoots in the lower reaches of the tree also quickly wilt and die. Leaves may form in the early stages of branch die-back but fall prematurely. Branch die-back stress is usually caused by fungus and can cause tree death.
Cankers usually form near the base of the trunk. These dark spots resemble irregular wounds on the bark and may weep sap or feel spongy to the touch. Cankers are indicative of stress from bark damage or infection from other sources, and will eventually lead to death if not treated.