Winter Tree and Shrub Care

News Column

John Wilson

Extension Educator

December 20, 2013

Winter Tree and Shrub Care Tips for Homeowners

Winter brings frigid temperatures, icy winds, and usually plenty of snow. Just as people battle Mother Nature at this time of the year, so do trees and shrubs, with one major exception: trees and shrubs can’t avoid exposure to the elements.

While your trees and shrubs seem to be in a state of hibernation in the winter, exposure to tough conditions can cause them major stress. Minimize that stress by helping your trees and shrubs through the cold months. If you take care of them in the winter, you’ll be rewarded next spring.

First, if you haven’t done so already, put a ring of an organic mulch, such as wood chips, around your tree and shrubs in late fall or early winter to help retain water and reduce temperature extremes. A couple inches of mulch will act like a blanket and give the roots a little extra winter protection. Mulch rings should extend out a minimum of three feet in all directions from the trunk of a tree or base of a shrub.

One word of caution when mulching trees and shrubs. Leave an unmulched area about 6-8 inches wide directly outside the trunk of a tree or base of a shrub. This bare area discourages voles from tunneling under the mulch and feeding on the bark of the tree or shrub over the winter.

Second, give your trees and shrubs a drink… especially during warmer periods when the soil will allow water to infiltrate. Winter droughts require watering as much as summer droughts. An occasional watering during the winter on trees and shrubs can be a life saver. This is particularly important to prevent winter burn on the needles of evergreens. But be sure to water only when the soil is not frozen or the water will just run off instead of soaking in the soil.

The soil should be moist to a depth of 18 inches in the root zone of trees and 12 inches for shrubs. You can tell how deep the water has infiltrated by poking a large screwdriver or thin rod into the soil. It will slide in easily if the soil is moist, but provide more resistance if the soil is dry. If it won’t go in at all, the soil is probably frozen.

And finally, pruning is third on our list. Winter is actually one of the best times to prune because it is easier to see the structure of trees and shrubs without their leaves. But limit pruning to deadwood and poorly placed branches in order to save as many living branches as possible.

Remember low hanging branches will never get any higher so this is a good time to start removing the lowest branches if they interfere with mowing or other activities in the yard. However, we don’t want to remove more than about 20 percent of the tree’s total canopy at one time, so removing low hanging limbs may be a two or three year process.

Conversely, many shrubs such as spirea, lilac, privet, and others respond well to severe pruning. If possible, remove the oldest stems at the ground level and leave the younger growth. Often the best way to rejuvenate an old, neglected shrub is to use a chainsaw and remove all growth as close to the soil line as possible without getting the cutting bar in the soil.

You may sacrifice flowers for a year or two, but this will improve the health and appearance of neglected  shrubs for years to come. Most evergreen and some broadleaf shrubs will be killed with this kind of severe pruning, so check to see how your shrubs will respond before cutting.

For more information on winter tree and shrub care, contact your local UNL Extension office.

John Wilson