The method of trimming dogwood trees depends on the variety. In general, trimming the trees includes removing dead and diseased branches when you notice them.
Cutting shrubby varieties of dogwood trees to the ground on a routine basis helps them grow new, colorful stems. This allows removal of the less desirable branches and stems, making room for better-looking stems. Other dogwoods don’t need much pruning aside from looking for dead branches and removing them. Trimming is optional for overgrown dogwoods. Also consider removing low-hanging branches periodically. It is best to prune in late winter and early spring, prior to new growth.