Chisago County Master Gardener
The following information was recently released by Gary Wyatt, University of Minnesota Extension agroforestry educator.
Drought conditions over the last two years have left trees and other perennial plants visibly stressed this fall. Tree stress symptoms include abundant seed production, leaf scorch, early fall colors, leaf drop, limb die-back and yellowing or browning of leaves and needles.
Fortunately, several measures can help enhance tree and shrub health.
Trees and shrubs should be watered generously until the soil freezes. This applies especially to conifers (pine, spruce and cedar) and trees planted in the last three years. Mulching newly planted trees helps conserve moisture and reduce winter root damage.
Young maples and thin-barked trees may benefit from sun scald protection, to prevent the bark from cracking in the winter and spring. Use plastic tubes or tree wraps now, and remove them in the spring. These practices can also reduce winter animal damage.
For other fall management practices, visit http://z.umn.edu/winterdamage.
Protecting trees from rabbits, mice, voles and deer is a major winter concern. Mow or remove tall grass to reduce mice and vole damage.
If the bark is removed or severely damaged around the tree, it will die. Protective physical barriers such as tree tubes, hardware cloth and fencing can be done when practical.
Odor, taste and visual repellents can deter many wildlife species, but may have inconsistent effectiveness. Human hair, soaps, garlic oil, hot sauce and animal repellents can be applied to branches and foliage to discourage browsing.
Weather, application frequency, animal population and feeding pressure affect the success of repellents. Alternate the repellents, since some animals become desensitized to them. A web resource that reviews prevention and control of wildlife damage can be found at http://z.umn.edu/critters.
If you’re unsure what’s causing problems in your landscape, University of Minnesota Extension has a great web site to help homeowners diagnose tree, shrub and plant problems or identifying a weed or insect: http://z.umn.edu/diagnose. This site links to the University of Minnesota Plant Disease Clinic and Soil Testing Lab.
Fall is also a good time to plant trees. Recommended trees for all regions of Minnesota are at http://z.umn.edu/rectrees. After planting, be sure to water until the soil freezes.
The best time to prune trees is during the dormant season from January to March. Flowering shrubs can be pruned in the summer after flowering.