Late winter and early spring are good times to give old or overgrown shrubs a new lease on life with rejuvenation pruning or renewal pruning, which are two slightly different techniques. Although pruning can be an intimidating task for many of us, these two methods are simple and effective.
In rejuvenation pruning, you cut all of the stems down to the ground in one go. That's it. Deciduous shrubs that respond well to rejuvenation pruning include:
Bluebeard (Caryopteris) -- done annually
Butterfly bush -- done annually
Renewal pruning is a multi-year process. Each year, you remove about a third of the stems, cutting them down to ground level. Choose the oldest stems each year. This opens up the shrub, letting more light and air in, and spurs new growth from the base. All of this will result in better flowering in subsequent years and a better shape and more manageable size. Deciduous shrubs that respond well to renewal pruning include:
Gray dogwood, red-stemmed dogwoods
Rhododendrons and azaleas
Image credit: By 4028mdk09 - Own work, CC BY-SA 3.0