take care when
pruning

By Barbara Arnold

Gardeners deal with innumerable frustrations. Insect control problems, dealings with squirrels, rabbits, and other small rodents, not to mention the weather, all compound to make the job of a gardener a rather difficult one. One needn’t further complicate the matter with untimely, though well meant pruning. Knowing when to prune flowering trees and shrubs can help alleviate some gardening headaches. Pruning improves the health of the tree by removing dead and dying branches, promotes air circulation, and allows more sunlight to reach the inside of the canopy.

Most ornamental trees and shrubs that flower before June 1 should be pruned right after they flower, including:

Buckeye and Horse chestnuts- Aesculus
Cherry- Prunus
Crabapple – Malus
Dogwood – Cornus
Filbert- Corylus
Forsythia- Forsythia
Fringetree- Chionanthus
Hawthorne- Crataegus
Lilac – Syringa
Magnolia – Magnolia
Pear – Pyrus
Serviceberry- Amelanchier
Redbud- Cercis
Vibernum- Vibernum
Weigela - Weigela

Those ornamental trees and shrubs that bloom after June 1 should generally be pruned in the winter or spring, before new growth appears. This list includes:

Blue mist spirea - Caryopteris
Buddleia – Buddleia
Goldenrain tree- Koelreuteria
Seven-Son Flower – Heptacodium
Smoke bush – Cotinus

When pruning any woody plant there are a few easy tips. Be sure to look for overhead utility lines, and if they are present, contact professional tree trimmers to do the job. If you are pruning overhead it is always better to have a second person assist you. First, remove any dead, dying and diseased branches. Especially when trimming trees, look for crossing branches that are rubbing against each other as this can create wounds where diseases can enter the plant. “Suckers” are rapidly growing shoots from the roots or base of the tree, most commonly found on crabapples and weeping cherries. These should be removed, along with the water sprouts that grow straight up from the interior of the tree. These sprouts and shoots don’t produce flowers or fruit, but they rob the tree of much needed sunshine and water. When pruning branches, look for the branch ‘collar,’ the thick part of the branch where it comes off the main trunk, and make your cut just above the collar. The collar grows like a callus and heals over the cut. If the collar is cut or damaged the tree is unable to heal correctly.

Remember, once the cut has been made, there is no going back. Look at the tree or shrub and take in the whole of its shape. If the branch is large, gently move it to see what part of the plant it is; this will give a good feel for what will be gone once the cut has been made. Annual pruning is best, because it only removes a small amount of the plant, keeping it from growing unchecked.

If the plant has become overgrown, the smartest thing to do is reduce over time, taking three years to prune, removing only one-third of the branches per year. Allow the plant to start shoots that will eventually become the new plant. This method works well for lilacs. Pruning to rejuvenate takes time, and many flowers can be lost, but in the long run the shrub will be healthier and more vigorous.

All that being said, we will look to hydrangeas. If properly cared for with the right conditions, fertilizer and water, many hydrangeas will bloom fully with little pruning, or none at all. For Hydrangea arborescens, such as “Annabelle,” prune back to about 1 foot in late winter, as these bloom on new wood. Leaving about one foot of stem after each year of pruning will let it grow thick and strong enough to hold the heavy flowers more upright. You still may need to stake the flowers. Pee Gee, Limelight or Tardiva, Hydrangea paniculata, bloom on new wood and should be pruned in winter and early spring.  It is not necessary to prune these every year. The fewer branches, the larger the flower panicles will be. Climbing Hydrangea, H. anomola ssp. Petiolaris, needs no pruning, just a bit of deadheading. Hydrangea macrophylla, which includes “Endless Summer” and “All Summer Beauty,” contains some of the new varieties that bloom on both old and new wood, enabling them to flower all summer long. It is important to note in pruning these to keep them deadheaded, and be careful not to damage the new buds found immediately below where the deadheads are removed.

Before pruning ornamental plants, do a little research and answer some simple questions: when does it bloom, and what do I want to accomplish? For plants that bloom in the spring, it is smartest to prune right after the petals hit the ground. This gives the tree a good amount of time to heal, but more importantly ensures that one does not wait too long, consequently pruning off next year’s flower buds. With the plants that bloom later, prune in the winter and spring so that the plant has time to heal and new shoots can grow and produce flowers.

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