Question
i have a 3 foot dogwood that the leaves are turning black and falling off and bark coming loose at the bottom above the ground what might be happening or causing this?  What can I do? It is a red dogwood.

Answer
shonda:
Loose bark near the base of the tree may indicate insect borers that are notorious on DW trees at least here in Arkansas. Leaf blackening/drop may be an end result of this damage at the base.  You can gently peel back some of the loose bark and you might see holes in the wood or other insects that have set up housekeeping. It sounds like this is a newly planted tree. Might be transplant shock-that is the tree has not aclimated well to new surroundings. String trimmer damage is also a big killer among trees and shrubs- so good idea to be careful. Mulch up to 3' deep is good to help prevent this and it also helps conserve water in the roots.  Replacement may be a viable option for you to consider. You can get lots of good advise from a local garden center on planting/caring for these trees. These trees are typically very shallow rooted and thus are susceptible to drought stress so they need a lot of TLC when they are first installed. Best to plant these in the winter or very early spring.
Hope this helps!
Steve