According to Iowa State University, in winter deer survive by eating the twigs from trees and shrubs. These can include trees and shrubs from your landscape. Deer are most likely to invade areas inhabited by humans when their normal food supplies are diminished. But you can keep deer from decimating your trees and shrubs with a combination of repellents that deter deer. Though no repellent is completely effective, a combination of repellents will help to keep deer away.
Fence the area around your landscape. Deer are instinctively hesitant to enter enclosed spaces, so even lower fences will help to deter deer. Fences that are 8 foot or higher will keep deer completely out of a landscape, but even smaller fences will psychologically deter deer. An electric fence with tin foil or electrified tape on the fence will help to deter deer by delivering an electroshock to them.
Hang mesh bags filled with scented repellants around your trees. Deer are naturally repelled by the scent of soaps or unwashed human hair. You will need to replace the bags every few weeks with fresh hair or a new scent of soap for the bags to maintain their effectiveness.
Hang flashing items, such as CDs, from trees. These items will catch the sunlight and startle deer. Hang the tape from a cassette tape from tree branches. Deer may be startled by the sound that the tape makes as the wind blows through it.
Sprinkle tree limbs and twigs with a bad-tasting deterrent, such as cayenne pepper or bitter apple spray. Deer who sample the twigs rarely take a second bite after encountering the unpleasant taste. Taste deterrents should be reapplied after each rainstorm.
Mix a scented deterrent made of one part raw egg white and nine parts water. Place the mixture in a spray bottle and spray it over the limbs of your trees. The deterrent will rot over time. Although you may not smell the rotten egg, a deer will smell it and be repelled by the odor. Egg deterrents should be reapplied every few months.