Autumn Tree Care

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Oak leaves from Oakwood Cemetary, Red Wing MN (photo by Nancy Lizette Berlin)

This post is a University of Minnesota Extension News Release:

Media Contact: Allison Sandve, U of M Extension, (612) 626-4077, ajsandve@umn.edu

ST. PAUL, Minn. (10/14/2013)—Drought conditions over the last two-plus 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 dieback and yellowing or browning of leaves and needles.

Fortunately, several measures can help enhance tree and shrub health.

Trees and shrubs–especially conifers (such as pine, spruce and cedar) and those planted in the last three years–should be watered generously until the soil freezes. Mulching newly planted trees also helps reduce winter root damage.

Young maples and thin-barked trees may benefit from sunscald protection to prevent the bark from cracking this winter and spring. This usually involves plastic tubes or tree wraps, which are removed in spring. These practices can also help reduce winter animal damage. Other fall management practices which will help reduce winter damage to trees and shrubs can be found at http://z.umn.edu/winterdamage

Protecting trees from rabbits, mice, voles and deer is another 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 or fencing can be done when practical.

Odor, taste and visual repellents can repel 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 about what’s causing problems in your landscape, University of Minnesota Extension has a great website to help homeowners diagnose tree, shrub and plant problems or identifying a weed or insect. This site also has links to the University of Minnesota Plant Disease Clinic and Soil Testing Lab: http://z.umn.edu/diagnose

Fall is also a good time to plant trees; water them until the soil freezes. Recommended trees for all regions of Minnesota are at http://z.umn.edu/rectrees. 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.

Source: Gary Wyatt, University of Minnesota Extension agroforestry educator
For more news from U of M Extension, visit http://www.extension.umn.edu/news or contact Extension Communications at extnews@umn.edu. University of Minnesota Extension is an equal opportunity educator and employer.

Trees…After the Storm

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By Katie Himanga, Goodhue County Master Gardener

Does your columnar arborvitae look like this photo as a result of the May 2 snowstorm?

Look closely to see if the stems are broken. Those need to be cut at the break or removed entirely. Arborvitae has some ability to re-sprout from broken stems, but only time will tell how a particular tree will respond. For stems that are bent but not broken, some will stand back up on their own. Others won’t do it on their own but can be supported with a splint for a few seasons until they regain strength. Use a long bamboo pole, wood dowel or flexible fiberglass pole. The latter are used for tents and for supporting netting in the garden. Strap the splint to the bent arborvitae stem at several points along the pole with Velcro tape or soft rags. Check the stems every few weeks throughout the summer and loosen the ties as the stem expands.

For other types of trees with broken limbs… If the tree has just one or two, it may be best to remove each broken branch entirely. Make the final cut just outside the branch collar. If there are many broken branches but the tree is otherwise safe to leave in the landscape, it’s best to cut off just the broken part of each branch. Use sharp tools but leave as much live tissue as possible on the broken stub. Healthy branches will re-sprout from dormant buds and it might be possible to do restorative pruning in future years. Plan to have a Certified Arborist work on the tree during the dormant season beginning in 2-3 years.