Fall nights with freezing temperatures have returned, and while some gardeners welcome wrapping up garden chores for the winter, it is not time to relax yet.

Now is the time to wrap young and newly planted trees for protection against sunscald or injury from deer, rabbits, rodents and other winter damage. Smooth, thinly barked young trees, such as maple, crabapple, honey locust and lindens, especially benefit from wrapping, as they are at higher risk for winter damage.

However, do not apply tree wrap any sooner than October; and be sure to remove it in the spring. If tree wrap is left in place over several growing seasons, it can serve as a hideout for insects and disease. In fact, if left in place for many years, wrap can kill a tree if not removed, as it can girdle, or strangle the tree as it grows.

While tree wrap is typically made of a heavy crepe paper, a better solution for protection of young trees is the use of plastic tubing. White, perforated drainage tile can be used, by simply cutting the tube lengthwise to be placed around the tree trunk. Plastic guards can also girdle trees, so be sure to check regularly and remove them before the tree becomes too large. To protect from rabbit damage, height of the tube should measure 2 feet above anticipated snow level.

Adding mulch around a tree will also help to prevent mechanical damage. But be sure to avoid mulch “volcanoes”, as seen in some yards when folks mistakenly make a thick pile of mulch around a tree. This is not healthy for trees, as air and rain cannot reach the roots through the bulk; can cause disease; and rodents may decide to make it home. Mulch should instead be spread out to a 3 – 4 inch thickness, which is best for trees, as air and rain can reach the roots.

Wood chip mulch is best for using around trees. The mulch should not be in contact with the trunk, but best applied about an inch away from the trunk to avoid potential disease problems. Mulch should spread to at least a 2 ft circle in diameter around the trunk. The key here is that bigger is better! A larger area of mulch, even extending out to the dripline, is so much better for the tree. Why not “go green” and visit your local tree disposal site to obtain mulch to use?

Did you know? Do not use fertilizer when planting trees. As most Iowa soils contain sufficient amounts of nutrients for newly planted trees, fertilizers are generally not recommended at planting time. Avoiding fertilizer use also helps encourage tree root expansion into the landscape, rather than circling within the planting hole.

Horticulture Questions? Contact McCormick at yvonne@iastate.edu for information or advice.