by Diane Sagers
GUEST COLUMNIST
A spectacular flower show has been going on, one act at a time. Act one included the crocuses and a few other brave early bloomers. Act two included the daffodils and very early tulips. Act three brings out the later tulips, pansies, hyacinths and other spring crops. In close succession act three tumbles onto the stage with the flowering trees and shrubs joining the spring flower show.
Act three comes in waves as various shrubs don their spring finery.
Forsythia, viburnums, mock oranges, lilacs and others make a splash in their own times. Their spring color is glorious and then they settle down in green for the summer. Although the green leaves on these beautiful shrubs do add to the look of your garden, we love them best for their spring color. There are other shrubs that we plant for their green color, textures or possibly variegated leaves that add interest to the garden.
Maintaining shrubs includes doing some pruning. The questions are why, when and how?
The answers to the why of pruning are multiple. Proper pruning reduces or maintains the shrub size. Pruning removes dead, diseased, or broken branches and stimulates flower and fruit development. Pruning old, established shrubs rejuvenates them. Pruning decreases injury risks and/or property damage. Pruning shapes plants to help compliment the plant's natural growth or it can be used to shape them into the forms we desire such as hedges, espaliers and topiary.
The "when" to prune is a matter of timing. Different species are best pruned at their own ideal times.
Do not prune spring flowering shrubs during dormancy. That flower show they put on in the spring emerges from buds developed during the summer months. Cutting off branches after summer removes those flower buds and reduces the blossoms of the spring. Prune spring flowering deciduous shrubs within three to four weeks after they bloom.
Summer flowering shrubs blossom on new wood so cutting them back actually stimulates new flower buds. Prune summer flowering shrubs in the late winter or early spring during the dormant season before they begin to leaf out.
If you are uncertain whether your shrub is considered spring or summer flowering, examine the buds. Determine whether the plant forms flower buds on the previous season's or current season's wood. Examine the tips of the branches in the fall and winter. Flower buds are larger and more rounded than vegetative buds. If you find large, rounded terminal buds (the ones on the tips of the branches) in the winter, you will know that they will flower in the spring. Smaller, more elongated or pointed buds are leaf buds.
Generally, plants that bloom before June 1 are considered spring blooming. Those with inconspicuous, pointed buds in late summer will form flower buds on new growth during the next season.
Of course, there are exceptions to the rule. Forsythia and spiraea produce many small buds on side shoots and the vegetative and flower buds look a lot alike. Nevertheless, they are spring flowering shrubs. Anthony Waters spiraea, also a spring bloomer, continues to bloom for a long period.
The "how" of pruning involves looking at the shrub's basic form. If the plant sends multiple shoots out of the ground, the ideal pruning method is renewal pruning.
Begin by removing dead, broken diseased branches to the base of the plant. Then select about one-third of the oldest stems and remove those to the ground. The plant will send up new shoots to replace those. Follow the same procedure each year to keep a young-looking healthy plant.
To rejuvenate an old plant, use the renewal pruning technique. Remember that the rule of thumb for healthy pruning is never to remove more than one-third of the living portion of a plant at one time.
The first year remove one-third of the oldest stems. The next year, remove half of the remaining old stems. The last year, remove the last of the old stems.
If your plant has been allowed to grow without this kind of pruning for many years, you may find that the stems are so thick and closely packed that you cannot get in to select just a few. You may have to go in and cut back one section one year, another section the next and the third the following year or even cut the entire bush back at once. This will not create as lovely a specimen for a few years, but drastic measures are sometimes required.
While just clipping back the tops of the plants will reduce their height, it will also force a lot of dense bushy growth at the cuts creating a top-heavy look. Allowed to grow like that, the tops tend to shade out the bottoms of the plants and the leaves will thin out making it look even more top heavy. Clipping with hedge clippers is for hedges.
The good news is that if you make mistakes pruning these shrubs, you may set them back and reduce flowering, but you are not likely to kill the plant.
Removing spent blossoms on spring flowering shrubs makes them look a little better during the summer. It also means the plant will not expend its energy making seed and it can put that energy toward producing new growth and new flower buds for next year. However, removing spent blossoms is not a requirement for a healthy, attractive plant.
Enjoy your spring flowering shrubs with their brilliant flower show in the spring, then let them make a lovely green backdrop to other plants during the summer months.