Some people will tell you that there is no such thing as “deer proof.”
While it’s true that deer will eat just about anything if they are hungry enough, there are some plants that are safe from deer damage (i.e. the deer rarely eat them), some plants that are unsafe (i.e. the deer always eat them), and some plants where it just depends (e.g. they may eat yours but leave your neighbour’s alone, or they may eat just the tender tips but leave the rest of the plant alone).