LOP & LOSE
Sally McNamara and Janet Poore, Master Gardeners
While March is the ideal time to prune most trees and shrubs in your garden; note that it is NOT the time to prune those that bloom in the spring. Pruning your spring blooming trees and shrubs may kill blooms that are forming. These plants should be pruned right after they bloom in the spring. Read this article for valuable information about pruning some of your most beautiful spring blooming shrubs.
Blossoms that is. Patience pays for those spring blooming shrubs and small trees gracing your landscape. While March is the perfect time to prune almost everything else it is several months early for those spring flowering ones. Ideally, the plants listed below are best shaped RIGHT AFTER blooming, before next year’s flower buds are set. Even waiting a month or two after flowering to trim these plants can mean losing next year’s blooms.
Lilacs benefit by pruning AFTER blooming. Lilacs can be pruned very severely for renovation with the understanding that it may take several seasons of growth for a good flower show. Since lilacs live so long they often grow out of their appropriate space in the landscape with dead and unsightly sections. Often shade has been created over them over the years which makes them spindly and the flowers sparse. Pruning helps here but lilacs and shade are not a good mix. Unfortunately, lilacs will regrow from roots so removing them means repeat pruning of the new growth or digging out the roots.
The bright yellow flowers of forsythia are so welcome in early spring that patience here will definitely be rewarded. This plant tends to be rather rangy in habit and benefits from regular trimming to keep it attractive in all seasons.
AZALEA & RHODODENDRON
While most specimens really don’t need pruning because they tend to keep a dense, organized structure, some might need restraining, balancing or thinning in the inner areas for more light and air. In northern climates, azaleas tend to create larger, more dense and flower covered specimens if they are planted with more sun rather than more shade as in the south.
Hydrangeas are of two major categories: flowering on new wood and flowering on old, or last year’s wood. The key to pruning is to know which you have. Ones that flower on new wood can be pruned very aggressively and still produce a summer crop of vegetation and flowers. Ones that flower on last year’s wood should NOT be pruned early but do look better if old blossoms are snipped or snapped off early in the growing season. New flowers will be produced of course but the dead ones will sully the look.
Fortunately, Magnolia flower buds are very obvious. They practically scream: “don’t cut me!” Magnolias in a sunny location don’t need much pruning generally but they often do need removal of suckers around the trunk.
Mock Orange, Virburnum, Chokeberry, Serviceberry, Ninebark, Weigela, Spirea and Fothergilla are other spring bloomers which, if they need any pruning which most do not, should be pruned after flowering.
Photo Credit: Gurneys (1), Michigan Bulb Co. (2), University of Minnesota Extension (3,5) & Julie Harris (4)