Darn Deer

The deer are eating my bushes! I have an herb garden out back which appears to be unharmed, yet this poor bush is completely gone! You can even see bite marks! And I know it's deer because I've seen their tracks in the empty lot next to our house. It takes a lot for me to keep plants and such alive, so I'd really like to keep what I already have.

Any advice on what I can use to keep them away?!