|When should a Cornus florida and Cornus kousa be pruned?
|My approach is to prune a dogwood as little as possible. Past experience with them is that there is a direct relation between how prized and expensive they are and their willingness to die! Seriously, pruning can result in problems with cankers, so if significantly misdirected branches or broken branches necessitate removal, do so with sharp pruners, and dip the blades in rubbing alcohol between cuts. Don't attempt to make shaping cuts.
Dogwoods love to have their roots in a forest floor. Therefore give them a good mulch bed as wide as is practical. This also reduces competition from turfgrass and keeps the dreaded mover and weedeater away from tender trunk tissues.