Unfortunately, hungry deer can devour your plants overnight. You also can try odor and taste repellants that you spray on plants, but effectiveness is unpredictable. And unfortunately, all types of deer repellants are most effective before the four-legged friends become a problem in your yard. By planting deer-resistant plants, however, you can at least increase the odds that the hungry animals will browse elsewhere. But remember that there’s no such thing as deer-proof plants, only deer-resistant plants.