The dogwood is a very recognizable tree in south Georgia and is adaptive to many different soil types. It likes well-drained soils high in organic matter. You do not see dogwoods growing in poorly-drained soils in woods environments. They need good soil drainage and protection from drought.
We usually see the best results from dogwoods planted in association with larger trees that provide moderate shade. Dogwoods like partial shade. In the wild, the dogwood is commonly found as an understory tree growing under hardwoods and pines. Growth problems are more likely in hot, dry exposures.
I have answered quite a few questions concerning dogwoods in the past few weeks. Issues described to me concern dogwoods that appear to be struggling. Each time I drive to a location to look at dogwood problems, I see dogwood trees in others’ lawns that are experiencing the same symptoms. Leaves are showing signs of chlorosis (yellowing) and necrosis (burning at the tips.) Additionally, some are covered in leaf spots.
The first thing we considered is a common disease. Dogwoods frequently get a disease called Spot Anthracnose. The symptoms are reddish-purple spots on the leaves and flower bracts. We see Spot Anthracnose in the spring when flowers appear. We also observe Cercospora leaf spot in microscope samples. This is found on many ornamental plants and flowers. It turns out, these leaf spots are normal and are not the primary problem.
This conclusion lead to one other diagnosis. Weather conditions this spring/summer have proven to be sporadic with rainfall, though dry conditions predominantly have existed. I have discussed this matter with UGA Extension Pathologist Dr. Elizabeth Little in a few conversations over what I believe is mostly environmental stress.
Dr. Little says, “The die back of the new growth and the leaf loss is probably environmental. I have been seeing drought-like stress issues on dogwoods in the last month. It could be the rapid switch we had from a long period of cooler and wetter to very sunny and hot caused more drought stress damage than one would expect, especially on the younger foliage but all over the trees as well. The amount of stress will be site-specific and some trees may be more vulnerable than others. Weak trees with poor root systems will get more problems.”
In conclusion, we are seeing environmental stress on dogwoods right now. This is not only observed in Thomas County, but also much of the rest of the state. Dr. Little works in UGA’s pathology lab and diagnoses pathogens on ornamental plants and turfgrass. The sporadic temperatures and rain events have also played a role in Leyland cypress problems existing at this time.
For additional questions, contact Effingham County Extension Agent Sam Ingram at 754-8040 or firstname.lastname@example.org.