Trimming or pruning serves two purposes. First, it gives you the manicured, finished look that conveys to others, “I take care of my property.”
Second, and perhaps more important, is the fact that it strengthens the specimen. Trees and bushes that are trimmed are healthier and fuller. The growth is distributed throughout the bottom and middle as opposed to new sprung shoots that are thin and frail eminating from the top of the shrub.