Cane. In one season you can have a tall privacy barrier.
Downside, it's forever. If you don't like it, too bad, you can't kill it.
Plus side, it's useful for many other things.
Downside, it will spread quickly if you don't keep it mowed over and thinned out.
I had it when I moved here, so I deal with it. No shortage of tomato stake, bean poles or fishing poles!
Ben