Ready ... get set ... it's almost time to prune
Pruning is the hot topic here at the garden center.
Pruning improves air circulation and penetration of sunlight to trees and shrubs, which in turn can reduce the incidence of plant disease. Trees prone to diseases like shot hole, powdery mildew and leaf spot will all benefit from good seasonal pruning.
Before you pick up your pruners, remove stakes and guy wires installed with trees planted last spring and fall. Don't worry if an unstaked tree seems a bit unstable. A little swaying of tree stems results in sturdy, resilient plants.
First, cut away all dead or damaged branches and twigs. Here's how to tell if a branch, even without leaves on it, is dead or alive. Use your thumbnail or knife to scrape a little bark off the branch. If the color of the wood under the bark is green, the branch is alive and viable. If the color of the wood under the bark is white, it could go either way; if it's brown, that branch is dead.
Second, prune out branches that are growing back toward the middle of the tree or crossing other major branches. Removing these branches relieves center growth congestion of the plant and allows more air and sun to circulate throughout the structure. Every year I'm asked, "How high should I prune my trees?" Prune trees to a height from the ground that is comfortable to you, and looks balanced in the yard. I am 6'2" and don't like to stoop under my trees during cleanup, so my trees are pruned pretty high up off the ground.
Third, prune away branches that are growing down toward the ground instead of out, or in a direction that doesn't promote the shape you have in mind for that plant. Cut these branches back to the trunk, or to a branch or new shoot that is heading in the direction you want the plant to grow. Correctly pruned cuts should be at a 45-degree angle, with the lowest point of the cut opposite and even with the bud, the highest point about 1/4 inch above the bud. This will encourage the bark to repair and grow more quickly over the cut and encourage healthy bud growth.
Forsythia, lilac, quince, azalea and rhododendron have been using all their energies during the winter months to form flower buds. Wait to prune these spring bloomers until after their blooms have dropped, as new buds will not appear until next spring. Prune them now and their spring flower show will be lost. Why not enjoy the flowers first, then prune?
It's a beautiful day, your pruning shears, saw, and loppers are already out of the shed, and you hear your roses calling to you "prune me." The problem is that if you cut them back too early, they will start to sprout and the cold nights will burn back the new growth. Even worse, a severe winter storm could hit the area and kill back even established rose canes that have been pruned too early. Between pruning early and a late winter storm, you could end up with a six-inch stub of a rosebush. You'll have to trust me on this one; this is the school of hard knocks speaking. Wait until March to cut back roses. I'll write about pruning roses when the time is right.
Now is the time to begin applications of dormant oil sprays to trees and shrubs. Dormant oil kills insect eggs laid last fall and insects that might be wintering over in the garden. Dormant oil is highly effective at controlling the worms that get into the fruits of your trees. Using environmentally friendly dormant oil now reduces the need for more dangerous pesticides later in the growing season.
Sun scald is a problem that results from our warm winter days and very cold nights. It is a crack that runs up and down the length of the tree trunk, usually where the sun hits the bark. The sun warms the sap during the day; but then cold night temps freeze the trunk, causing a long split up and down the length of the tree. Older trees have thicker barks and enough branch structure to shade and protect themselves from sun scald. Younger trees benefit from white tree paint on their trunks to help reflect the sun until mid-spring, when they leaf out and shade themselves. Don't use house or industrial paint on trees or the plants will absorb some of the toxins from the paint and transmit them to the fruits, flowers and leaves.
Visit us here at the garden center for more answers to your pruning questions. For you online gardeners, there are more detailed pruning instructions on my web site at wattersonline.com under "garden talk topics." Another good source of pruning instruction is the book How to Prune Fruit Trees, by R. Sanford Martin.
Until next week, I'll see you in the garden center.