Living in one of the worst parts of San Francisco, my wife planted a rose bush called a Mermaid rose in a few places. It's an heirloom variety that is extremely hearty so needs very little water or any other type of attention whatsoever, and it grows like a weed. It has flowers on it basically all of the time AND it has the most vicious, recurved thorns of any rose. It literally grows by leading with a thorn and the things are sharp down to a nano-size tip... it'll snag your skin without you even realizing it until you try to pull away. The canes are trunk-sized once the thing gets established haha. If we had one here in WA I'd expect to find dead deer and other animals stuck in it weekly
Anyway... recommended since it looks nice, takes little care, and can effectively barbed wire around the foundation of your home or along fences, etc.