Two factors contribute to deer in peoples’ yards: lots of deers, and people often clear understory shrubs and trees in wooded areas. This is considered ideal deer browse, but now they must look elsewhere because that material has been removed.
To protect trees and shrubs, it may be necessary to "fence off" deer so they can’t prune important landscape plants. Spray-on repellants work during summer because they have a bad odor. Those same repellants in the winter do not keep their unpleasant qualities in the cold air. It is necessary to find other ways of protecting trees and shrubs. Fences can be the traditional vertical barrier that is secured to posts, or you might be able to use the same fencing material in a different manner.
If a fence is installed in the usual manner, wooden or metal posts are sunk into the ground and some kind of wire fencing is secured to the posts. If the fencing is installed too close to the trees or shrubs, the hungry deer just pushes into the fence and feeds. Always put the fencing on the outside of the posts so the posts help to strengthen the fence. The fence should not be placed too close to the plants. A gap of 3 or 4 feet should work. If the fence is too close, using a single electric hot wire with insulators at the very top of the fence will put a jolting end to fence-leaning.
Another possibility is the same fencing material used horizontally. Place concrete blocks on the ground in a zigzag pattern surrounding what needs to be protected. Sit them on their ends so they are 16 inches tall. Unroll woven wire or other fencing that is at least 4 feet tall, placing it flat on the top of the cement blocks. When the fencing is complete, a deer will not attempt to step into the fencing and possibly get its legs entangled. The fence is placed 2 or 3 feet from the tree to be protected. Make sure corners are closed so no deer can find a gap in your Great Horizontal Wall. To make the fence more noticeable, wire a few jingle bells to it so it makes noise if bumped. Smart gardeners might consider this value-added idea.
In the spring, don’t be too hasty to remove the fence. March to the middle of April is too early for Michigan and regions with a similar climate. Growing plants begin to be tastier in May and until that time, deer are sticking to their high fiber diet. That could include your woody ornamentals. Then, roll up you fencing and put the concrete blocks away for another season.
For more information on protecting your landscape or garden year-round from deer, see "Discouraging deer year-round in your yard: Facts versus fantasies." For information on deer-resistant plants, see "Deer-Resistant Plants For Homeowners."