I got a news letter about a product that is supposed to make the plants taste bad to all animals its called repellex from austree inc. I have never used it or known anyone that has but it may be worth a shot.
Garden Center I work at sells a product called liquid fence which has been very effective, says our customer who continuely come back for more. Contains rotten eggs and some other ingredients, but will not wash away and repell many different animals, the smell eventually goes away as well. But yea any type of plant from the pine family should do, juniper, spruce, etc.