Dogwood anthracnose is a serious fungal disease that has killed large numbers of flowering dogwoods across eastern North America since the late 1970s. Caused by the fungus Discula destructiva, it attacks leaves, twigs, and branches, and can kill a mature tree within two to three years if conditions favor the disease. If you’re seeing brown-spotted leaves, dying lower branches, or clusters of sprouts along the trunk of your dogwood, anthracnose is a likely culprit.
What Causes It
The pathogen behind dogwood anthracnose, Discula destructiva, was first identified in the 1990s but had been spreading through forests and landscapes for at least a decade before that. It overwinters inside diseased foliage and stem cankers, then reactivates in spring when temperatures are cool and moisture is abundant. Early in the growing season, tiny fruiting structures erupt through the bark of infected twigs and on the undersides of spotted leaves, releasing massive numbers of spores.
Those spores travel by splashing rain and wind to nearby shoots, leaves, and flowers. The fungus requires abundant moisture, humidity, and shade to cause disease, which is why dogwoods growing in cool, damp, shaded locations are hit hardest. Trees in full sun with good air circulation are far less likely to develop severe infections. Hot, dry summer weather slows the disease considerably, but a wet spring or a prolonged cool spell can trigger explosive spread.
How to Recognize the Symptoms
Dogwood anthracnose typically starts on the lower branches and works its way up. The earliest signs are tan or purple-bordered leaf spots that appear in late spring, often starting at leaf tips and edges. In wet weather, spots enlarge rapidly, and entire leaves can turn brown and cling to the branch rather than falling normally. That clinging of dead, brown leaves through summer is one of the most distinctive visual clues.
As the disease progresses, it moves from leaves into the twigs through the leaf stalks. Infected twigs develop sunken, discolored cankers, and the branch beyond the canker dies. The tree responds by sending out clusters of small shoots (called epicormic sprouts or water sprouts) along the trunk and larger branches. These sprouts are themselves highly susceptible to infection, creating a cycle where the fungus keeps moving closer to the main trunk. Once cankers girdle major branches or the trunk itself, the tree declines rapidly. Severely infected trees often die within a few seasons.
Which Dogwoods Are Most Vulnerable
Flowering dogwood (Cornus florida), the native species across most of the eastern U.S., is highly susceptible. Pacific dogwood (Cornus nuttallii) on the West Coast is equally vulnerable and has suffered devastating losses in its native range. The disease has been especially damaging in forested mountain areas where cool temperatures and high humidity create ideal conditions for the fungus.
Kousa dogwood (Cornus kousa), native to East Asia, shows significantly greater resistance. It isn’t immune, but it rarely develops the severe twig dieback and trunk cankers that kill flowering dogwoods. Hybrid crosses between flowering and Kousa dogwoods, sold under the Stellar series and similar trade names (varieties like ‘Aurora,’ ‘Constellation,’ and ‘Stellar Pink’), combine the spring-blooming habit of flowering dogwood with much of Kousa’s disease resistance. If you’re planting a new dogwood in an area where anthracnose is present, these hybrids or Kousa types are the safest choices.
Conditions That Make It Worse
Anything that keeps foliage wet and the canopy humid favors the fungus. Shaded sites surrounded by taller trees, low-lying areas with poor air drainage, and north-facing slopes are high-risk locations. Overhead irrigation that wets the leaves compounds the problem. Drought stress also plays a role, not because it helps the fungus directly, but because a water-stressed tree has fewer defenses. Trees that are weakened by drought one summer are more vulnerable to infection the following spring.
Over-fertilizing creates another opening. Excess nitrogen pushes out soft, succulent new growth that is especially susceptible to infection. A light, balanced fertilization in early spring is fine, but heavy applications do more harm than good on a dogwood dealing with anthracnose pressure.
Managing an Infected Tree
There is no cure for dogwood anthracnose, but good cultural practices can slow the disease and often save a tree if it hasn’t progressed too far. The strategy centers on reducing moisture around the canopy, removing infected tissue, and keeping the tree healthy enough to outgrow the damage.
Prune out all dead or dying twigs and branches during dry weather. Remove every water sprout or sucker on the trunk and larger limbs, since these provide easy entry points for the fungus to reach the main stem. Make cuts well below visible cankers, into healthy wood. Clean up thoroughly: in fall, rake and remove all fallen leaves, and pull off any dead leaves still clinging to branches. This sanitation removes a huge portion of the fungal material that would otherwise overwinter and restart infections in spring.
During extended dry periods, give the tree a deep soaking at the root zone. Avoid wetting the foliage. Maintain a 2- to 3-inch layer of composted mulch over the root zone to conserve moisture and buffer soil temperature, but keep the mulch a few inches away from the trunk itself. Too much mulch piled against the bark creates a moist environment that invites other problems.
Fungicide sprays can provide an additional layer of protection, particularly for high-value landscape trees. Products containing chlorothalonil or mancozeb are commonly recommended. Timing matters more than the product: applications need to begin at bud break in spring and continue at regular intervals through the period of active spore release, typically every 10 to 14 days during wet weather. For large trees, this usually requires professional application. Fungicides are preventive, not curative. They protect healthy tissue from new infections but won’t reverse damage that has already occurred.
Planting to Avoid Problems
Site selection is the single most effective defense. Plant dogwoods where they receive morning sun and good air circulation. Edges of woodlands, eastern exposures, and spots with some overhead canopy thinned out are ideal. Avoid deep shade, valley bottoms, and areas hemmed in by buildings or dense plantings where air stagnates.
Never dig native dogwoods from the woods and transplant them into your landscape. Wild trees may carry the fungus without showing obvious symptoms, and moving them can introduce the disease into a neighborhood that was previously unaffected. Buy nursery-grown stock from reputable sources, and favor resistant varieties when they’re available for your area.
For existing trees that are healthy, the same cultural practices that manage the disease also prevent it: annual pruning of dead wood, fall leaf cleanup, appropriate watering, moderate fertilization, and maintaining air flow through the canopy. A well-sited, well-maintained flowering dogwood can live a long life even in regions where anthracnose is present. The trees that die are overwhelmingly those growing in heavy shade, under chronic stress, or left unmanaged as the disease quietly builds year after year.