I live in Philadelphia (midatlantic US region) in a small closed-in backyard, because of the urban environment, the conditions seem to be harsher than most, as my yard is one of the only on the block that is not paved over. Last year my dogwood started shedding some bark on the branches, it seems to have started from pruning cuts I had made, although the large branch that is completely shed, started shedding from a break after a strong storm. All the pruning cuts were done in very late winter/early spring. Not sure my next move, I am very worried about my tree, I am afraid to cut it anymore. It started flowering about 2 weeks ago, and the flowers and leaves look good. Thank you.
It could be a few things, and it certainly is worrisome. My suggestion is to call / email the Philadelphia County Extension and speak to Master Gardeners local to your area to see if someone else has been experiencing similar symptoms: Horticulture Questions Hot Line (Philadelphia County Master Gardener Program) (my initial thought is borers of some kind, additional reading here: http://extension.umd.edu/sites/extension.umd.edu/files/_docs/programs/riparianbuffers/IPMDogwood.pdf If so, the local Master Gardeners will know if there are such infestations locally)
