For folks that live in neighborhoods pestered by petty crime, or worse, AND that want to bring some habitat into their yard, there's nothing better than cholla. For homes on flats in most of Tucson, chain-fruit cholla is the natural choice (Cylindopuntia fulgida), while teddy-bear cholla favors the caliche and rocks of foothill slopes (Cylindopuntia bigelovii). To do the job you just need a bucket and tongs to collect some cactus joints from unwitting donors. It won't hurt them. Then you drop them where you'd like your fence to grow, skootch a little dirt around the fallen joint and water. Voila!
With supplemental water, they grow pretty fast, meaning within five years you should have something to talk about. And you'll be talking about lizards first, then quail. At the same time, another species, Homo thiefians, will be repelled by your spiny wall. Really. They just look around and choose the easier target, and cholla definitely are part of the equation.
Got questions? Email me at email@example.com.