Did you know that your trees need care throughout the winter to maintain their health? Or that you need to start that care now, before a big freeze hits?
Even though trees in the urban areas are now going into dormancy, they require attention throughout the winter to stay strong and be prepared for the upcoming spring.
Here are four tips to follow:
- Use mulch. Apply a two- to four-inch layer of wood chips, bark or other organic mulch spread over the root system of the tree to help reduce soil evaporation, improve water absorption and insulate against temperature extremes. To prevent rodent damage and the possibility of rot, make sure that mulch does not rest against the trunk of the tree by applying it in a doughnut shape around the tree’s base, a hands-breadth away from the trunk. In most cases, there is no need to fertilize trees. Consider layering leaves around the base of each tree as natural mulch.
- Prune. Although trees can also be pruned in the summer during active growth, late winter is often a favorite time for pruning due to the improved visibility of a tree’s limbs and structure when its leaves are gone. The main reasons to prune a tree are for safety, health and aesthetics. First, assess your tree and determine if it is developing a healthy branch structure. Remove dead, broken and crossing branches and improve a tree’s form, but make sure you are doing it correctly. Always prune at the branch collar – the point where a branch joins a larger one – and don’t remove any branches without good reason. Follow this link to find out more about pruning trees. Plus, we recommend first-time pruners sign up for a workshop, such as UW’s Center for Urban Horticulture, Plant Amnesty, Seattle Tilth and City Fruit
- Wrap the trunk. Some recently planted thin-barked trees such as honey locust, maple or linden are susceptible to bark-damaging sunscald and frost cracks when temperatures fluctuate in fall and winter. Wrap trunks of younger trees up to the first branches using commercial tree wrap to protect the bark. Remember to take the wrap off once weather warms in the spring.
- Give them a drink. If this winter brings long periods of dry weather (two to three weeks without rain or snow) and the ground is not frozen, it is a good idea to give your trees some water. Water trees throughout the dripline of the tree – the area from just outside the trunk to the outer edge of the longest branches. Trees need about 10 gallons of water per inch of tree diameter. Long, slow watering will assure that water reaches down into the root zone.
If a newly planted tree has a Gator bag or other watering bag around its trunk, it is best to remove it during the winter months. During winter, these Gator bags can attract mice and other small mammals who may like to snack on the bark of your young tree. Remove watering bags until we are past frosty weather.
Always call an arborist for consultation if concerns are identified. A certified arborist is trained to use best practices that will keep trees healthy and looking good. Arborists can identify branches that have problems and ones that could be a future hazard.
A little investment into trees when they’re young can lead to beautiful trees that help cool homes in the summer, block winter winds, and add character and property value. Your care for them will provide benefits for years to come.
If you have any questions or want more information on urban tree care, contact DNR’s Urban and Community Forestry Program.