Question: I wish you could see our garden. It looks like a jungle. We know this is the time of the year to prune, but where do we begin? Can you offer any suggestions?
Answer: Unfortunately, without knowing which ornamental trees and shrubs you have growing in your landscape, it is impossible to provide specifics. There are some very general guidelines however, that are helpful in pruning just about any plant. If you will keep the following goals in mind when you begin your pruning operation, you will be pleased with how easy the task becomes. First, simply remove dead, diseased or damaged wood. Next, eliminate those branches that are rubbing, interfering or poorly placed. And finally, prune to enhance the natural growth habit and shape of the plant.
As you prune, remember that trees are unable to heal wounds the way animals do. Plants grow callus tissue in response to an injury. This tissue grows over the wounded area, but the damaged tissues are not repaired. Trees also chemically wall off the wounded tissue, in a process called compartmentalization.
Making pruning wounds as small as possible so the tree can close the wounds more quickly. The longer a wound remains open, the more chance it has to develop a problem such as internal decay. Much of the pruning literature still recommends the traditional flush cut, making the cut as close to the trunk or branches as possible. Recent research has shown flush cuts may open large wounds, which may not close rapidly. Thus, flush cuts may be more susceptible to decay and eventually cause the death of large sections of the trunk above and below the cut.
Prune to accentuate the tree's normal shape. When planting young trees, do not prune one-fourth to one-third of the top as is sometimes recommended. Severe pruning at the time of planting may reduce shoot and root growth the following year.
Question: What are thinning cuts?
Answer: A thinning cut removes a branch to its origin of growth or point of attachment. Pruning a branch back to another branch, a branch to the main trunk, or the main trunk back to a large branch are thinning cuts. Thinning cuts are helpful in directing growth to the remaining branches or trunks of the tree, retaining the natural form of the tree and avoiding vigorous sprouting at the site of the cut. Thinning cuts also reducing rank, undesirable, vigorous, sucker growth, allow more light to the center of the plant, decrease wind resistance and reduce potential disease problems.
Question: Every time we prune a tree, it seems to produce a thicket of water sprouts. What are we doing wrong?
Answer: Water sprouts or suckers sometimes emerge when a tree has been severely pruned. These almost always grow from a stub cut. Species such as crabapples, hawthorns, and flowering plums, produce many of these vigorous shoots-always poorly placed and interfering. Prune them when young or physically rub them off when they are quite small (right after the shoots emerge).
EDITOR'S NOTE: For answers to local gardening questions, contact Master Gardener Rachel Gana at 642-8723 or e-mail her at: firstname.lastname@example.org.