I bought a little silvery one a while back at a Tropiflora plant sale. Hm, have to go hunt for it, I haven't seen it for a while. Maybe it got stuck onto some animal or other and walked away? Poor animal!
Yes, I had concluded that they were just too 'toothy' for my garden. But if I needed a barrier to keep dogs off a lawn, that would for sure be my 'go to' plant!