A few words of caution, first. Do not prune tender trees and shrubs such as nandina, magnolia, camellia, hebe and hardy fuchsia this week. Wait until the weather warms in late spring to prune cold-sensitive plants because pruning always stimulates growth – and you want these light sleepers to remain in the fog of winter dormancy. Instead, make your cuts on fruit trees and overgrown but hardy deciduous trees and shrubs.
My question is about pruning. How do you know when and how much to prune a tree or shrub? K.K. Tacoma
The old rule says that the best time to prune is “when the shears are sharp.” That is meant to stop the procrastinators who never get around to pruning because they blame the time of year. In our climate, you can prune most plants during their dormancy from November to February.
The best source for details on how to prune and what to prune in Western Washington is either the website www.plantamnesty.org or the book “Cass Turnball’s Guide to Pruning” written by the founder of Plant Amnesty. This nonprofit organization is dedicated to “ending the senseless torture and mutilation of trees and shrubs caused by mal-pruning.” The information is presented in a spirit of fun and education and the author lives in Seattle so she understands our unique climate.
How does one prune fruit trees? Do you have to prune fruit trees? N.H., Olympia
You can increase the fruitful bounty of most trees by thinning inner branches so more sunlight reaches the blossoms. You can prune fruit trees nearly any time of year, but in the winter it is easier to follow the shape and form of the tree.
You don’t have to prune fruit trees to keep them alive – only if you want more fruit or to train the tree to stay low or thin so that the fruit is easier to harvest.
Here’s how to thin to allow more sunlight to hit the fruit. You just cut off a thin or inward facing branch at the joint where it sprouts from a larger branch. A thin branch is anything less than a finger width wide.
When pruning pear or apple trees you also can make “heading” cuts. This is when you shorten a long branch so that you leave only two or three buds. Some orchardists call this type of cut “tipping back” and it encourages more fruiting spurs to emerge from the newly cut branch.
Pruning is a skill best learned by demonstration and local nurseries, Plant Amnesty and Master Gardener clinics offer hands-on pruning demonstrations this time of year, including at the Tacoma Home Show Jan. 25-29 and the Northwest Flower and Garden Show Feb. 8-12.
When is the best time to top some tall trees that might fall on my house? R.W., Maple Valley
Never. Topping trees removes the “leader” or highest growth point and this messes up the apical dominance. Soon the lower branches left behind grow wide and crazy creating a sail that can be caught up in the wind and take down the entire tree left behind. Hire an arborist to evaluate the health of the trees you fear and perhaps thin, but never top large trees.
Marianne Binetti is the author of “Easy Answers for Great Gardens” and eight other gardening books. She has a degree in horticulture from Washington State and will answer questions from her website at binettigarden.com.