If you want a hedge that no one will get near, barberry. We used to have kids that cut thru my dad's property when I was a kid. He planted barberry hedges around the perimiter of our property, and no one in their right mind would try to get near them.
They have stickers about 3/4 of an inch all over them. The bad part is trimming them, your arms will look like you got in a fight with a pissed off bobcat. My dad finally got the trimming part figured out. He just hit them with a hedge trimmer, used a leaf rake to get the trimmings out of the hedges, then ran a mower over the trimmings so you didn't have to handle them.
The plants are hardy, and grow pretty fast.
