Deer, like people, have their preferred foods and will always go for them first. If a plant is unappealing to a deer he will likely pass it by. Spiny leaves, thorny stems, offensive odors and strange, new plants are characteristics of plants deer don't like to eat. However, if the deer population is too great for the amount of available food, or the winter is exceptionally harsh, deer are known to eat even plants they would normally reject.
Most Disliked Trees
Rutgers University rates the following trees as rarely damaged by deer: American holly, bottlebrush buckeye , dwarf Alberta spruce, Japanese black pine, katsura tree, nimosa, paper birch, pawpaw, pitch pine, red pine and the river birch.
Seldom Damaged Trees
The following are examples of trees that seldom are severely damaged: Allegheny serviceberry, Chinese fringe tree, Colorado blue spruce, common sassafras, dawn redwood, douglas fir, eastern red cedar, eastern white pine, European ash, green ash, honey locust and the paperbark maple
Most Disliked Shrubs
Shrubs and bushes that are the most deer resistant include arrowwood viburnum, barberry, bayberry, blue mist, broom, bush cinquefoil, butterfly bush, common boxwood, daphne, devil's walking stick, fragrant sumac, heath, heather, Japanese plum yew and the Lydia Morris holly.
Seldom Damaged Shrubs
Shrubs almost as deer resistant include armstrong juniper, autumn olive, beautybush, blue star juniper, blueberry elder, buckthorn, Carolina silverbell, cherry laurel, common witchhazel, dwarf balsam fir, English holly, forsythia, hazelnut, inkberry, and mountain juniper.
Spray-on treatments can protect trees and shrubs but often times have to be repeated after a bout of bad weather. Fences help if they are high enough, or if the area they cover is small. Deer dislike jumping into an smaller enclosed area. Hanging shiny reflective aluminum pie pans work for a while but the deer eventually become used to them. Having a dog available to guard the trees will keep the deer away, and if it is not possible to have a dog, scattering the scat of one around the plants will often fool the deer.