You laid out some serious cash for shrubs and trees for your yard. The last thing you want to do is kill them off or damage their growth pattern by cutting them back at the wrong time or in the wrong way.
In our zone (most of Iowa is zone 5), most deciduous trees are dormant in the winter. Spring blooming shrubs need to be pruned after the bloom season and before they set buds for next year or they won’t bloom for you this season.
Summer bloomers are OK to prune in late winter or early spring as the plants are not concerned with producing leaves or flowers for a while and can devote their resources to healing the cuts.
Many diseases that might affect trees and shrubs pruned in warmer weather are not an issue in the winter months. To avoid oak wilt, always trim oaks during dormant months from December to February. Midwinter thaw days, when the sun shines and the snow melts, are perfect for getting your trimmers out.
But before you grab those lopers, take a gander at those branches. Know your tree and how it naturally grows. Don’t try to make a weeper out of a columnar tree or a round shrub out of a vase shaped one. Highlight the natural shape and remove branches outside of that form.
Cut back to a bud or a branch, never leaving a stub. Remove crossing or rubbing branches, unless they are crucial to the form of the tree, to open up the canopy as well as any suckers or water sprouts.
Step back and walk around the plant often to see it from all angles. Leave a natural collar when removing a large branch from a tree, never cutting the branch flush with the trunk.
ARTICLE CONTINUES BELOW ADVERTISEMENT
Crown reduction is the strategic removal of branches to shorten the overall height. Do not top off a tree or shrub as it will cause permanent changes in the natural shape of the plant. Crown raising is the removal of branches from the ground up to add clearance from the sidewalk and ground. Crown thinning is removal of crossed or crowded branches within the tree.
Evergreens, for the most part, require no pruning. Their drooping branches actually add support for the tree.
Be sure to look for diseased branches or possible pests as you trim. Be safe and take care of your tools. Clean cutting tools with a mild bleach solution after your done to remove any fungus or insects. Wear protective eyewear and avoid cutting overhead branches. Steer clear of power lines and overhead wires. Make sure tools are sharp and clean before starting.
Pruning need not be a daunting task. Just remember to prune during those winter thaw days in February when the ground still is too frozen for gardening.
l For gardening questions call the Linn County Extension Hortline at (319) 447-0647.