Thinking out loud... hedge...
The south corner of my yard looks like crap, it's overrun with small caraganas and invasive daylilies. I would like to rip everthing out and plant an impermeable hedge because people keep cutting through my yard.
One idea I had was double-flowered plum. I have some questions though. How big do they get? Do they sucker? Would they make a good informal hedge? Is there anything else I should know about growing them? Oh yeah and do they have thorns?
I also thought of a really prickly rose hedge such as a larger rugosa. Nobody would cut through that. But I'm not sure where I could buy enough of the same rugosa to make a hedge, economically. I would probably need a minimum of 25 plants.