Q. Why are the leaves wilted on the top half of my 30 year old beautifully full dogwood?
This has been such a dry summer that I would guess that drought conditions are responsible for the wilting that you are seeing. This may be stressing the tree and resulting in the growth of leaves closer to the lower part of the tree as you describe. Make sure that the tree is getting adequate watering. That said, remember that dogwood foliage does turn color in the fall. You are probably concerned that it is still too early for the foliage to be turning. Here is a link to a fact sheet from the U. S. Department of Agriculture: http://www.plants.usda.gov/plantguide/pdf/pg_cofl2.pdf that may be helpful.