I have some areas I would like to plant some deterrent plants. Preferably fast growing ones so that rules out cacti. We have some pampas grass but I'm not a big fan due to it's shedding.
+1 on blackberries and roses. Blackberries grow like crazy too. Be careful not to let them take over. They can get large enough to act as a hide. Good source of food too: pie, jam...getting hungry. And rose hips have tons of vitamin C (but don't taste like, well, anything.)Let's not forget blackberries. Can make an impenetrable barrier as well as providing a delicious crop.