Dogwood leaf spots and browning leaf edges
The leaf spots you are seeing are a symptoms of a fungal disease called dogwood anthracnose (Elsinoë corni). This is fairly common on flowering dogwood trees in Maryland and tends to be more severe in years when we have very wet spring weather. It is not as much of a problem in drier years. Here is our webpage about this disease and our management recommendations. Rake and discard symptomatic foliage.
Since disease severity is sporadic depending on how wet the spring season is routine fungicide applications are not recommended. https://extension.umd.edu/hgic/topics/spot-anthracnose-dogwood-or-elsino%C3%AB-leaf-spot
Flowering dogwoods are prone to several problems if they are not growing in optimal conditions. For example, if the tree is located in a full sun area or if we have periods of drought (as we did late last summer) you should provide irrigation to minimize stress on the tree. Refer to our webpage for additional information on care for dogwood trees, https://extension.umd.edu/hgic/topics/flowering-dogwood-trees-selection-care-and-management-disease-problems