Shrubs may form a dense hedge or be like little trees.

The one downside to many shrub varieties is their annual sucker growth. Suckers are shoots growing from the base, the root crown and surrounding area roots. I have seen decades-old lilacs ignored and allowed to run nature’s course. They don’t look too bad, but so thick that a mouse might need a map. It becomes impossible to tell where the lilac and its many shoots begin and end. Indeed, there is no end; it is just one huge old lilac whose upper circumference is matched by that of the width of its shoots. These old tangles are a major pruning job and take hours to clean out. If you have the space and can live with extra-shaggy, then don’t prune.

Little tree method:

Most shrub pruning is done to achieve specific visual goals, and a look I call “little tree” is the most popular. Little tree refers to a shrub that has been cleaned out at the bottom, all suckers removed, and a balanced group of clean old stems left to spread and flower. This allows light to get to the surrounding soil so that under-story plants can also thrive. It also shows off the shrub to its best. Almost all flowering shrubs that we grow look very good pruned this way. The secret to yearly maintaining shrubs in little tree mode, is this: when the new suckers appear and are only inches high and still green, they can be easily pulled out by hand. No saws or loppers are required. When small green suckers appear—and they will—pull them out by hand while you still can. Perhaps another garden task is not what you were looking for but this is the easiest and cheapest method of all.