Dogwood Problems

Poor flowering - Dogwoods grown from seeds will vary in their flowering ability, the age at which they will start flowering, and the number and size of flower bracts produced. Excessive shade or nitrogen will limit or prevent flowering. Sometimes, a heavy flowering and fruiting dogwood will flower less the following year. Dogwood flower buds develop during the summer and should be visible at the ends of branches in the fall.

Leaf scorch - Dogwoods have a rather shallow root system. During periods of hot, dry, windy weather, the leaves may become scorched (brown on the margin and/or along the midrib). Mulch and water as needed during drought.

Dogwood borer - is mainly a problem on trees which have been physically injured by lawn mowers or weedeaters. The insect larvae needs an injured area in order to penetrate the bark. Plant symptoms include off-colored foliage, wilted terminal shoots, and crown dieback. Large branches may die. Trees under stress from drought, compacted soil, or grown in full sun are especially prone to borer attack. Borers are difficult to control after they enter the trunk. Provide optimum growing conditions to reduce stress, mulch to eliminated bark injury from equipment, and avoid pruning April through June. Spray in late May to early June when dogwood borers eggs are laid by adult moths.

Powdery mildew - appears as a white substance on both the upper and lower leaf surface. Leaves may become twisted or deformed and may develop a chlorotic mottle. While powdery mildew will not kill a tree outright, it can weak it thus causing it to become susceptible to other disease and environmental factors. For control, avoid excessive nitrogen fertilizer, improve air circulation, reduce other stress factors, remove plant debris in the fall, and use resistant cultivars.

Spot anthracnose - small, reddish-purple spots appear on infected flowers, leaves, stems, and fruit. Infected leaves may fail to develop normal leaf size and shape; flower bracts may be spotted or fail to open properly. The fungus overwinters on twigs and fruit - fall cleanup of debris is recommended.

Dogwood anthracnose (Discula distructiva) - is a serious fungal disease that has killed dogwoods in the northern portions of the United states and western North Carolina. The most noticeable symptom is twig and branch death beginning on the lowest branches. The disease can be recognized by purple-ringed leaf spots and brown, dead leaves that cling long after normal leaf drop. It can be fatal to dogwoods growing in moist, shady locations, especially those stressed by environmental conditions (poor drainage, drought, soil compaction, acid rain, low pH, limited sunlight). For the disease to develop the dogwood must be exposed to prolonged periods (10 to 14 days) of cool ( in the 60s and 70s) and moist conditions. Dogwoods in landscape setting that receive adequate sunlight (half day of direct sun or high filtered light) and air circulation are normally not affected. The disease occurs at high elevations in the North Carolina mountains but is not a problem in the piedmont or coastal plains.

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