Ten year old Dogwood wilting, dropping leaves
Greetings, I am in Brooklyn have a 10-11 year old Dogwood - it is late June and it has dropped green leaves and appears to be wilting. Also there appears yellow spots. She in North facing front yard - some good sun 9-12:00. Hate to lose her. Thanks Hal Bernstein
The position of your tree should be fine as dogwoods appreciate some protection from harsh afternoon sun. It also needs rich, acidic, well-drained soil, so checking the soil's pH and that there is no compaction at the roots is a good start. You can have the soil pH tested through the Westchester County Cooperative Extension. Information on collecting and submitting a soil sample can be found by following this link. Adding some compost to the soil for nutrition and soil texture each year is a good idea.
If the soil isn't draining well, the roots will not be able to bring up the nutrition the tree needs for the soil. The same is true if the pH isn't right. If the soil extends too far up the tree's trunk, roots can grow near the surface and strangle the plant so keep the soil level below the trunk flare.
Your dogwood also benefits from a 2 inch layer of mulch that will help keep the soil around the roots cool and moist during the hot dry months and simulates its natural woodsy habitat.
Dogwoods are susceptible to a good number of diseases, particularly dogwood anthracnose, but I do not see the telltale dark spots on the leaves that identify that disease. Here is a link to a fact sheet on that disease so you will know what to look out for. Powdery mildew can cause dogwood leaves to yellow and fall but is not likely to kill the tree.
Attend to the cultural care of the tree to keep it strong in the case of a viral or fungal attack. If you notice damage to the trunk or presence of insects, please let us know.