Let the pruning season begin! This is Part One of a two-part series covering common flowering shrubs in our diocese and their pruning needs. Part One covers spring flowering shrubs and Part Two will cover summer flowering shrubs, including flowers that grow on older wood.
The perfect flowering shrub has been purchased, carefully planted, and irrigation needs have been met. Correct pruning techniques are a terrific way to keep your flowering investment healthy, happy and filled to the brim with blossoms.
Important: All pruning should be done with clean, sharp tools. Clean tools work better and last longer. Plant diseases can be spread by dirty and contaminated pruning tools. Wash soil from tools and scrub with a stiff brush. Dip tools into a diluted solution of household bleach, using ten parts water to one part bleach. Shears, knives, loppers, pruners, and shovels all require occasional sharpening. Dull blades can be sharpened by you (don’t forget your protective gear) or by the local sharpening shop.
Barberry: Limit pruning to removal of dead or weak growth and to direct growth for shaping. It can be sheared if turned into a hedge, otherwise prune after flowering. Larger, older canes can be removed at the ground to provide room for new, strong sprouts.
Dogwood (shrubby types): As canes become old (more than 1–1½” in diameter) saw them off close to the ground. This is especially important in maintaining vibrant stem colors during the winter, as older canes develop a dull gray bark. Another option is to annually cut the entire plant down to under 6” off the ground in early spring. This keeps the plant smaller and it will consistently have brightly colored stems in the winter. Low growing varieties are best left alone.
Forsythia: As canes become old (more than 1-1½” in diameter) saw them off close to the ground to provide room for new sprouts. It’s important to keep up on this as the plant can quickly develop a wild, gangly look if neglected. Prune immediately after flowering.
Lilac: As canes become old (more than 1-1½” in diameter) saw them off close to the ground to provide room for new sprouts. When neglected eventually there will be a clump of base stems topped by a little green foliage and fewer flowers. Take a close look at the plant each spring to see if there are any canes to remove. You may not need to cut them every year, take a look then make that decision. Do not shear these plants.
Mock Orange: This has a tendency to get woody, dilapidated, and sparse without pruning. Cutting back or removal of the older stems is important to yield fresh, lush new growth. A good general guideline is to not have any growth older than five years. Prune immediately after flowering.
Pyracantha: It’s best to site the plant properly in the beginning which will reduce or eliminate the need for regular pruning. The plant will look its best with little, if any pruning (excellent for espalier display). If you have to trim it up it’s best to say a quick prayer before you start (they have very sharp thorns)! Sparingly prune right after blooming. Since the main attraction is the berries, limiting the growth pruned is best. When too much is taken off the berry display will suffer.
Serviceberry: Same as Forsythia.
“For flowers that bloom about our feet; For tender grass, so fresh, so sweet; For song of bird, and hum of bee; For all things fair we hear or see, Father in heaven, we thank Thee! For blue of stream and blue of sky; For pleasant shade of branches high; For fragrant air and cooling breeze; For beauty of the blooming trees, Father in heaven, we thank Thee!” —Ralph Waldo Emerson
(Kerry Peetz is a master gardener and a member of Sacred Heart Parish in Colorado Springs.)