Will trees and shrubs recover from the weight of snow and ice?
Gardening columnist Don Kinzler addresses whether or not plants will recover from a rough winter and ways gardeners can help them along.
What did the tree do when it went on sabbatical? It took a leaf of absence, of course.
Tree humor is fun, but what’s happened to trees this winter is certainly no laughing matter. Wet heavy snow, followed by cold temperatures, left many branches bent and broken since mid-December. Will trees and shrubs recover?
Coworker Joe Zeleznik, North Dakota State University Extension Forester, described the situation in a recent article. He said “The blizzard in mid-December was especially bad, starting with a thick layer of ice. After that came the heavy wet snow. Finally, the light fluffy snow came and eventually the storm moved on.”
“How are the trees doing with all these challenges?” Zeleznik asks. “Most trees are doing fine,” he says, “While others sustained a good deal of damage.”
Zeleznik points out that trees that hold their leaves into winter have been most affected, and ironwood and Ponderosa pines in his own yard are still bent from the extra weight of ice and snow. Spruce trees fared better, he notes.
I’ve noticed the same in our own yard. Some trees and shrubs are unaffected, while the branches of other types are completely bent out of shape. Our evergreen columnar arborvitae, whose branches form an upright column, are now splayed apart, looking more like a haphazard mess than its normal, tailored shape.
Zeleznik continues “I’ve been debating what to do. Should I knock off the snow and ice from my trees? Would pruning out the deformed branches be a good approach?” He reminds us that “do nothing” is always a management option; it just has its own set of consequences.
“I don’t know if the leader on our pine tree will straighten out next year, if I remove the snow. The stem could be permanently kinked. If I cut out the bent-over leader, I worry that multiple leaders will form, creating a structural nightmare in which connections are weak and more susceptible to future breaking.”
Zeleznik observed that many multi-stemmed arborvitaes and junipers were badly affected, which is what I’ve found in our own yard. He says recovery is possible, though it will likely take several years.
Zeleznik suggests drawing the stems back together and supporting them with a strap or flexible material such as a bungee cord. Wait, though, until temperatures are warmer, in the 30s when stems are flexible.
He says arborvitae and other multi-trunked types will need support for one to two years as they put on new wood underneath the bark. The extra rings in the trunk will give the tree strength and stiffness.
Zeleznik emphasizes that support straps should be flexible, providing support without digging into the stems. Check straps every three or four months to be sure they’re not choking the stems, and loosen as needed.
Beyond that, Zeleznik says all we can do is wait, and hope we don’t get more super-heavy snow and ice.
I totally concur that binding together the branches of arborvitae does work. As a college student, I worked at the home of NDSU Professor Neal Holland during summer break. A duty one spring was to bind together the stems of columnar arborvitae, which had become splayed outward during winter. The material of choice at the time was old nylon stockings, which worked perfectly. The arborvitae regained their structure and were still standing tall many decades later.
Deciduous (leafy) shrubs that are flattened by snow and ice are better able to rebound than evergreens. Many such shrubs in our own yard have lost their rounded shapes. Instead, branches of spirea, ninebark and others have fallen under the weight of heavy snow, laying at unnatural angles.
Luckily, the entire shrub can be pruned all the way back to six inches above ground level before spring growth starts, and new, sturdy branches will quickly form, returning most shrubs to their original shapes. Unfortunately, this method doesn’t work for evergreen shrubs.
As Zeleznik pointed out, only time will tell the full extent of this winter’s damage.