Deer are beautiful animals and it's exciting to see one around your home, at least until you find that they've eaten all the blooms off your roses. They like the mixture of farms, woods and suburban housing that we create and will eat many different types of ornamental plants. Deer are not grazing animals and cannot digest grass well but do need a large quantity of leaves during the summer, six to 10 pounds a day per animal.
Fences can be used to protect plantings, especially vegetable gardens, from deer damage but they need to be tall, seven to eight feet for a wire fence. Solid fences that the deer cannot see through can be lower, about five feet. Deer can jump a 10-oot fence, but would rather not, especially if the cannot see what is on the other side. Fences are expensive, however, and may not be practical for a small garden. Electric fences can be used to discourage deer. One of the easiest kinds to install is a "peanut butter fence," several charged wires with peanut butter applied to entice the deer to make contact with the wire. The resulting shock trains them to leave the area alone. You can protect the trunks of young trees from deer damage by using plastic sleeves and bird netting can be placed over the branches to discourage nibbling.
Once deer acquire the habit of browsing in your garden it's difficult to deter them. However, a number of deer repellents are sold, some containing predator urine, eggs or substances that give a bitter or unpleasant taste to foliage. All need to be reapplied regularly. The most effective seem to be the egg-based repellents such as Deer Away, reported to be 85 to 100 percent effective. You can make a similar repellent at home with an egg beaten up with a quart of water. Squirt this around vulnerable plants such as roses using a dish detergent bottle. You won't be able to smell the egg but the deer will and avoid it. A solution containing cayenne or hot sauce can be sprayed on non-edible plants, especially the new growth, or on vegetables before the edible part such as the tomato or the broccoli head develops.
Given enough other food, deer will often avoid strong smelling plants such as herbs, but when hungry may eat almost anything. Look for plants resistant to deer in your area before you landscape, but be aware that very few plants are completely "deer proof."