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Winter Protection for Trees & Landscape Plants
submitted by Don Janssen, UNL Extension Educator
Failure to protect fruit trees and landscape ornamentals against gnawing rodents and rabbits this fall can result in a nasty surprise next spring: girdled trees.
Mice and rabbits often feed on the bark of fruit trees and ornamental plants. Mice generally do their dirty work beneath the concealment of tall grass, snow or mulch that laps up against the tree trunks. Rabbits sit on top of the snow and gnaw on the trunk and branches. Therefore, protection must extend from the soil to 18 to 24 inches above the usual snow depth.
The first step in protecting trees against rodents is to mow and trim around trees, remove shrubby vegetation and eliminate woodpiles, stacks of lumber, brush piles and other materials that would provide hiding places for mice and rabbits.
Because it takes only one gnawing animal to do a great deal of damage, more aggressive measures are also necessary to protect trees. These fall into two categories: taste repellents and physical barriers.
Chemical taste repellents work by making the bark taste bad so that animals looking for an easy meal look elsewhere. Thiram, the most commonly available taste repellent, works best when it's mixed with a resin "sticker" and applied at 20 percent concentration.
Apply any taste repellent from the soil to well past the usual snow level. Spray the trunk and low-hanging branches that rabbits might be able to reach. If snow drifts unusually high around valuable plants, a midwinter spray might be necessary to extend protection higher up the plants.
Taste repellents can be fairly effective if animals have other food sources available nearby. But if animal populations are so high, the weather so severe or food so scarce that the animals are nearing starvation, they will eat even the nastiest tasting stuff to survive.
When animal populations are high, trapping or poisoning can make repellents more effective by reducing animal numbers.
Several dozen mousetraps won't cost very much, and running a trapline is easy, though time consuming. To keep traps from catching small birds, place them in thick vegetation and under shrubbery where mice are likely to go and birds are not. Bait them with a mixture of peanut butter and either oatmeal, saltine crackers or wild birdseed, and check, empty, rebait and reset traps daily. This can eliminate large numbers of mice in just a few days.
Another way to avoid trapping birds is to put baited traps inside cardboard boxes, tin cans or other containers with openings so small -- 1 inch in diameter -- that only a mouse can enter.
An advantage of traps is that they have little potential to harm pets or non-target wildlife. Poison baits, even the multiple-dose anticoagulant types, can harm humans, pets and wildlife. Place mouse baits at the entrances to mouse burrows and in mouse runways, or in bait boxes that make the bait inaccessible to pets and other non-target animals.
University of Nebraska-Lincoln Extension in Lancaster County is your on-line yard and garden educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office
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