Pruning trees and shrubs in the home landscape can be a mystery and a source of anxiety to many folks. This is especially true it seems when it comes to pruning needled evergreens. Well, fear not. Needled evergreens that are not planted as hedges or for topiary usually don’t need much pruning other than to remove dead, diseased, or damaged branches. When removing these branches, just cut back to their point of origin on the main stem or back to a healthy lateral branch.
Keep in mind that junipers, arborvitae, chamaecyparis, hemlocks, pines, spruce, and firs typically do not have live buds on old wood. Therefore, pruning to control shape or size should be light and confined to a portion of the new growth. Never cut shoots back into the old leafless wood.
Most needled evergreens should be left to develop their natural shape. They should not be sheared except to create formal shapes since shearing results in a very dense shell of needles at the outer regions of the plant and causes excessive shading on the interior portions. This in turn leads to premature shedding of the inner needles, creating a dead zone in the center of the tree or shrub. The evergreens mentioned above do not regenerate new branches or needles from old wood to fill in the dead zone.
Corrective pruning of pines, spruce, and firs should be done while the trees are still young. Once they are overgrown, corrective pruning cannot be done without destroying their natural shapes. If the main stem of young specimens of these trees has unusually long internodes (distance between needles), which creates a very sparse looking plant, pinch or cut off about one half of the new growth. Do this now before the new needles have lengthened. This will promote more branching and a denser plant. Do not do this routinely every year as it may lead to excessive shading of the interior of the tree. To restrict the upright growth of these trees, similar pinching of the leader or main stem may be done. If a young tree should develop more than one leader, remove all but one. If a leader is damaged, it can be replaced by tying one of the lateral branches in the top whorl of branches to a vertical brace.
It is not unusual for low-growing and creeping junipers to become overcrowded. In that case, remove entire branches by selective thinning, or by cutting back to stems pointing outward. This is best done in early spring. When doing this pruning, do not leave stubs. If there are branches that have diseases or have been winterkilled, remove these as just described.
Of the needled evergreens, yews and hemlocks are the most tolerant of shearing, which is why they are so often used as hedges. Shearing of these should be done in spring after most growth has occurred, but do be careful not to cut back into the aforementioned dead zone with hemlocks. Since yews produce live buds all along their stems, they can be cut back as far as desired. However, if hard pruning is needed to rejuvenate an old yew plant, do it before it begins new growth in spring.
Do not prune this list of gardening tasks for this week:
- Be careful when cultivating around peas and onions. These plants have shallow roots that are easily damaged. Placing a layer of straw mulch around the plants will protect them from heavy-handed cultivation while also helping to keep the soil cool, something which favors the roots of peas.
- Need some garlic now for a recipe? There is no need to buy garlic bulbs at the supermarket if you are already growing garlic. Yes, the plants are still immature, but you can pull up a plant and use the young bulb and the leafy shoots to flavor recipes.
- Pinch back the shoots of herbs, such as basil and oregano, when you see flower buds forming. This will encourage growth of new shoots and leaves, making for better harvests of the tasty herbs.
- Keep planting container-grown herbaceous perennials, shrubs, and trees. Current weather conditions still favor planting. Nevertheless, be sure to moisten the soil a few hours before planting and then again immediately after planting, that is, if Mother Nature has not performed that task for you.
- Water flowering annuals the day before planning to cut some flowers for indoor arrangements. This will ensure that the plants, and specifically the flower stems, are turgid when cut. That will extend the vase life of the flowers. Many annuals, e.g., annual poppies, will continue to produce flowers through the summer if the flowers are routinely harvested. Too many cut flowers for your use? Then share them with friends.
- Plant miniature roses in patio containers or window boxes for something out of the ordinary. You'll have the neighbors drooling — an ugly sight to be sure. Miniature roses range in size from about 6 inches to a couple of feet. They can even be brought indoors for the winter and will continue to bloom if given bright light.
- Don't forget Father's Day is a week away! A garden tool would make an ideal gift. Dads love to putter in the garden. That’s much less stressful than putting on a golf green.