Pruning is a gardening task that many regard as a chore. True, pruning certain plants can be daunting and tricky, but it's well worth the effort. It's beneficial—essential, even—to the health of your plants and the look of your garden.
Thank goodness for books likeThe Pruner's Bible and Pruning Made Easy, which help make the process a little less arduous. The former offers illustrated directions for pruning 80 of the most popular trees and shrubs; it even suggests the best tools. The latter goes even further, offering step-by-step guidance with more than 300 illustrations.
There are many good reasons for pruning trees, particularly: root and branch pruning at transplanting time, pruning to train a plant or to correct a problem, pruning out dead or diseased limbs, and pruning to rejuvenate an older plant all serve a clear purpose. Pruning to control the size of a plant may be necessary in some landscapes, but can frequently be avoided by selecting a plant that will not outgrow the site. Check out The Homeowner's Complete Tree & Shrub Handbook; it contains a great section all about the pruning and maintenance of trees.
I've found that pruning grafted ornamental trees—like Hawthrones and Crabapples—can be especially tricky. Many grafted ornamentals are prone to a particular problem that should not be allowed to go unchecked—the rampant growth of suckers and water sprouts (sometimes called water shoots or epicormic growths). Water sprouts grow upright from the branches, often in clumps, and frequently at the site of previous pruning cuts or wounds. Suckers, originating from the roots below the grafting point, grow quickly and prolifically and can obscure the true form of the tree if left unchecked. In older or neglected trees, both suckers and water sprouts can be so thick and dense that they not only look messy but can weaken the tree by drawing nutrients away, encourage disease by blocking air circulation, and decrease fruit and flower production.
The easiest time to prune any tree is during winter dormancy when crossed branches, water sprouts, and other problems are easier to spot. Because extreme pruning in late winter may lead to excessive suckering the following spring, it may be best to perform major pruning in late summer when regrowth is slow. While broken branches should always be removed immediately, spring pruning during active growth is not usually recommended, in part because the wounds will be more susceptible to diseases such as fireblight. Traditional advice has been to prune water sprouts and suckers as soon as they appear, but some experts now advise waiting until growth slows before cutting back succulent growth.
Poorly performed pruning is easy to spot—the "stop and chop" approach common to utility companies who routinely "top" trees and maintenance crews who chop out branches without rhyme or reason leave a trail of disaster in landscapes across the country. While judicious removal of limbs may help air circulation and create a stronger branching habit, indiscriminate or careless cutting can be deadly. Large limbs should be cut back to a live branch or to the central trunk of the tree, being careful not to leave a stump that will give easy access to insects and diseases. To avoid larger limbs from breaking away during the pruning process and tearing the bark, first make an undercut, then cut the limb through above that point. Remove the stump as close to the trunk or limb as possible without wounding the tree.
The rule of thumb in the past was to paint over pruning cuts and other wounds with a paint or tree sealant to guard from disease, and there are still followers of this school of thought. However, many experts today believe that trees will naturally seal cuts and wounds with cambium growth and that the sealants are unnecessary, and may even slow the healing process.
So remember, gardeners: If you want healthy, well-maintained plants, pruning is necessary—but with a little help from trusted gardening guides, it doesn't have to be a thorn in your side!