Our landscape and urban trees are preparing for winter dormancy and could use a little extra care before and during the cold weather months, to help ensure a good start in the spring.
The summer drought placed trees in an overall water deficit, predisposing them to potential health and pest issues when the growing season arrives next year. Young or newly established trees will require the most attention because of the limited water resources in their growing environments.
Tips for winter preparation include:
- Trunk wrapping. Smooth or thin-barked trees like honeylocust, crabapples, linden and, especially, maple, are susceptible to sunscald and frost cracks because of the temperature fluctuations from sun exposure in the winter. Prevention includes guarding the trunks of younger trees up to the first branches using a flexible, white tree wrap. Leave the wrap on until after the last freezing temperatures — usually Mother’s Day.
• Mulching. Apply 2-3 inches of wood chips, bark or other organic mulch over the root zone of the tree. Start at the base, but not against it, to the edge of the outer branches or drip line. This will reduce soil evaporation, improve water absorption and insulate against temperature extremes.
- Pruning. Late fall and early winter is an acceptable time for limited pruning of most tree species. Functional pruning is the only reason to prune at this time. Prune trees to remove dying, diseased or dead branches, or to improve structure. Be sure to use proper pruning practices as outlined in Trees Need a Proper Start: Prune Them Right (FAQ-19-W), found at Purdue Extension's The Education Store.
- Watering. Whenever rainfall is insufficient for extended periods of 2-3 weeks or more, supplemental water is needed, especially on newly planted trees and those less established. A proven recommendation is to use the 5 + 5 rule, which says to provide 5 gallons of water plus 5 gallons for every diameter inch of tree trunk. This should provide plenty of water to help the tree during times of inadequate moisture. For mature and well-established trees, a good rule is to provide 1 inch of supplemental water every week or so to keep leaf moisture adequate. It is advisable to water plants though the fall until the ground is frozen, so that trees have adequate moisture to survive the winter months and are ready for spring growth. The best time for winter watering is on warmer days, when snow has melted and the temperature is above 40 degrees.
These simple maintenance guidelines will help get trees off to a good start after the long winter, when we are ready to transition from the snow white to the growing green.
To find more information on this subject check out:
Purdue Forestry and Natural Resources Extension, Tree Installation: Process and Practices.
Indiana Department of Natural Resources, Tree and Shrub Coverts.