Flowering dogwoods are understory trees. In the wild they grow in the cool, moist shade of larger trees, with leaf litter over their roots. In a sunny lawn, with grass competing for water and a mower bumping the trunk, they are under constant stress, and stressed dogwoods attract borers and disease. The good news is that many declining dogwoods are suffering from stress, not a fatal problem. Fix the conditions and the tree can recover.

Table of Contents

The short answer: to revive a dogwood, first find out why it is struggling. Then water deeply, 1 to 2 inches a week in dry periods as Clemson Extension recommends, and spread a 2- to 3-inch layer of mulch over a wide ring around the tree, kept off the trunk. Remove grass from the root zone, prune out dead and diseased wood in dry weather, protect the trunk from mowers and trimmers, and avoid fertilizing a drought-stressed tree. A dogwood with dieback that reaches the trunk, or extensive borer damage, is unlikely to recover.

Step 1: diagnose before you treat

Clemson Extension lists the main causes of dogwood problems as fungal pathogens, insect feeding, environmental stress and unfavorable growing conditions. Look for:

Spotted, blotched leaves and twig dieback, starting low in the crown: dogwood anthracnose or leaf spots.
White powder on leaves: powdery mildew.
Holes, sawdust-like frass or rough, swollen bark near the base or at old wounds: dogwood borer.
Scorched, curled leaves in summer: drought or too much sun.
Pale green leaves: the Morton Arboretum notes flowering dogwood prefers acid soil and gets pale green leaves in high pH soil.

For a detailed symptom guide, read why your dogwood tree is dying. If you are unsure, take a sample to your county extension office.

Step 2: decide whether it can recover

What you see	Outlook
Leaf spots or mildew, mostly healthy crown	Good
Some dead twigs, scorch after a dry summer	Good, with better watering and mulch
Several dead branches, borer damage on one side	Fair
Dieback reaching the trunk, borer damage around the trunk	Poor; plan to replace

Step 3: water properly

Clemson Extension says dogwoods do not tolerate extremely wet or dry soils and should be watered deeply, 1 to 2 inches per week, during dry periods, especially in sun. Because flowering dogwood is shallow-rooted, Clemson notes it may be among the first trees to suffer drought injury if not mulched and watered. The Morton Arboretum also lists dogwoods among drought-sensitive trees to check more often.

Check the soil before watering. The Morton Arboretum suggests digging down with a trowel: if the top inch or two is moist, there is no need to water.
Water deeply rather than lightly and often. The Morton Arboretum recommends wetting the soil at least 5 to 6 inches deep.
If you use sprinklers, Clemson advises watering in the morning to reduce the risk of leaf disease.
Do not overcorrect. Soggy, poorly drained soil is also a problem for dogwoods.

Step 4: mulch a wide ring

Clemson Extension recommends a 2- to 3-inch-deep ring of mulch at least 8 to 10 feet across around a mature tree, without placing mulch directly against the trunk. Pine straw, compost or ground bark keep the shallow roots cool and moist. The mulch also keeps lawn equipment away from the trunk.

Step 5: remove the competition

Grass roots compete directly with a dogwood’s shallow roots for water. Replacing turf under the canopy with mulch is one of the most useful things you can do.

Step 6: protect the trunk

Clemson Extension notes dogwood borers attack newly planted trees, trees in poor health, trees under drought stress, and those with trunks damaged by lawn mowers or weed trimmers. Mulch beneath the canopy reduces the chance of trunk wounds. Never use a string trimmer near the trunk.

Step 7: prune out dead and diseased wood

Clemson Extension recommends pruning dead and infected twigs and branches and raking up fallen leaves to reduce disease. Cut back to healthy wood just outside the branch collar, in dry weather, and clean your tools between cuts. For timing and technique, see how and when to prune a dogwood.

Step 8: fertilize only when it helps

Clemson Extension suggests fertilizing dogwoods lightly in spring, after frost has passed, with a balanced, extended-release, acid-forming fertilizer such as an azalea fertilizer. It also says to avoid fertilizing trees stressed by drought during summer. Fertilizer is not a cure for a struggling tree; water, mulch and protection come first. A soil test will tell you whether nutrients or pH are actually a problem.

Step 9: consider the site

The University of Maryland notes flowering dogwoods do not tolerate full sun, hot and dry conditions, poorly drained sites or saturated soil. If your tree sits in a hot, sunny, exposed spot, it may struggle no matter what you do. A young tree can sometimes be moved to a better spot while dormant. An older one may be better replaced with a dogwood suited to the site, such as a disease-resistant cultivar.

Step 10: be patient

Recovery is measured in seasons, not weeks. Look for healthier leaves and fewer dead twigs next year. If your recovering dogwood is healthy but not flowering, read why a dogwood is not blooming.

When to call a certified arborist

Call a certified arborist if you see cankers or borer holes on the trunk, if dieback keeps spreading, or if the tree is large. The ISA Find an Arborist directory can help.

Sources

Dogwood, Clemson Cooperative Extension HGIC
Dogwood Diseases and Insect Pests, Clemson Cooperative Extension HGIC
Growing Flowering Dogwood Trees, University of Maryland Extension
Flowering Dogwood, The Morton Arboretum
Watering Trees and Shrubs, The Morton Arboretum

Top photo: Derek Ramsey, CC BY-SA 2.5, via Wikimedia Commons

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