There is a method of controlling shrub size and keeping flowers that gives an overall natural look. Briefly, we start the shrub on what I will call a recycling program.
This method works on all shrubs. In fact, the more prolific the natural suckering, the better. This is what we are going to take advantage of—a shrub’s ability to grow new shoots after the stimulation of pruning out a percentage of its old branches.
The old guys
Any ten-year-old shrub, pruned little during that time, will be a collection of branches whose ages vary from one to ten years old. It will be the old guys—the eight-, nine-, and ten-year-olds, that are outgrowing the space allotted or conceived; the ones that are reaching out to the point where you feel the visual effect is impaired.
This work is best done in spring or fall, leaving the plant alone during the growing season. Using a hand saw or loppers, remove some or all of the old guys. Once these are removed, the shrub will look different right away. You might be done. Stand back and look. With a little touch on the sides, a bit of polish, this year’s work is done. What this means is that you have room in that spot for an eight-year-old shrub of that variety.
Let one year go by, leaving the shrub alone to recover from the pruning. A year later from your spring or fall pruning, let’s inspect. The eight-year-olds are now nine and there are lots of new shoots. Can you live with it another year? No, eight years seems to be what I prefer.
Great, let’s prune. Because there are so many small one-, two-, and three-year old shoots, let’s thin some of those, but not all. Any areas of the root crown that are overly thick with new shoots can be thinned. Use your Felco secateurs for this and cut to ground level.