
You may not realize it, but winter is a very important season for tree health. We typically think our deciduous trees drop their leaves and go dormant and don’t need any attention. Yet, this fall and into the winter, the trees need us to show them some love.
Water. If we haven’t had any natural precipitation for 2-3 weeks, your woody plants will need a drink. My strategy is to put the hose on a trickle and water each tree for 15 minutes, and each shrub for 5 to 10 depending on the size. I use the timer on my phone to help me remember to move the hose. It is especially important to water any trees, shrubs or perennials that you planted this past fall.
Wrap it up. Use tree wrap on young trees to prevent sunscald. Young trees have thin bark which can crack in extreme temperature fluctuations, creating an unsightly wound that inhibits the tree’s growth and takes years to heal. For more information about sunscald, see this information sheet from CSU extension. Zip ties work well to secure the wrap; duct tape does not.
Hold the salt. If you use a de-icing product on your walk or driveway, be judicious and use only when needed. Once it warms up and the ice is gone, sweep up the remaining particles of ice melt. These products often include salt which will alter the soil salinity and can damage plants and especially large trees.

- Control scale insects. Aspen trees, among others, are often infected with scale insects, as seen in this photo. Scale type insects suck the sap of the trees and weaken the tree. Since scale insects spend most of their life cycle under a hard, protective cover, they are resistant to insecticides. You can control this insect by taking a scrub brush and gently scraping them off the tree. In the winter, it is easier to remove the scale since the tree doesn’t have leaves and the insects definitely fall to the ground and die.
Cut it out. Winter and early spring are the best time to prune trees and other woody plants. Pruning in the dormant season is less stressful on trees because it doesn’t interrupt their growth cycles, disease and fungi spores are also dormant reducing the risk of infection, and it’s just easier to see where the tree needs to be trimmed. It is especially important to trim young trees so they grow with good structure. For larger trees, hire a certified arborist.