I would plant P. Bissetti, it's supposed to be super dense, super cold hardy and may eventually engulf your neighbors house as well (heh heh!). Another good one is yellow groove, it's even hardy where we are, I think it gets taller than bissetti. Though since you are in zone 6b/7a you could plant some nice p. nigra (black 'boo), but that doesn't work as good as a screen, but it gets super tall.

I empathize with you, we are surrounded by neighbors who have done atrocious things, one kept pushing the property line and setting up tree stands in our nice old oak trees (and put nice 16 D nails in the trunks too), the others liked to steal motorcycle parts and chickens. I should get my revenge and plant bamboo on their properties, hee hee hee!

lol.yes I want something dense and tall. The built very close to the property line but 300 ft from my house so i can use something that screens well

Try to kill 'em with kindness via bamboo. : ) Bissetti is supposed to be the most vigorous and dense of all, I had gotten one from bamboo plantation two years ago, but my hubby had decided to plonk a cord of wood in front and behind it which shaded it too much and so it didn't do so well...plus we have moles which are tunneling everywhere here and they disturbed the root system. It did send up some small growth last year, and I hope it survived the winter (went -6 below, not much snow cover) so we'll see. For fastest growth you may want to get a large size pot. If your soil is decent it should take off. I usually get mine via online from bambooplantation.com. If you want to sell boo poles you would probably want the bigger boos like p. nigra, p. henon (gray bamboo) or something like that. Once bamboo gets started, it really goes hog wild.

Good luck with your neighbors, hopefully you can talk to them. Ours are insane, but the younger ones aren't so bad, the biggest troublemaker moved 2 doors up the road. So we got em on both sides of the road. Ha, I bet our neighbors are worse than yours, lol!

During the past years we've lived with them, some of the things they've done are: pointed a shotgun at my husband as he drove by (judge never did anything), made up lies to get the cops to come out here, tried to run my husband off the road when he was on his motorcycle, stole our chickens and other stuff, they burn toxic plastic and tires (they actually burned one of their trailers down and got a fine for that, ha ha!), threw out pieces of raw meat in front of our house in the middle of summer so it would stink the whole place up. Life in the country sure wasn't what I thought it was going to be. That's just a few of the things they've done, like kicking in our door when we were building our house, trying to get us in trouble with the township supervisor (friend of theirs). Our only crime was moving next door to them. Most everyone out here hates their guts, which is some consolation. Hope your neighbors aren't as bad as ours!

As mentioned Bissettii is a very good choice. Bissettii is very very cold hardy and very very dense with culms. As someone mentioned on some other forums, his bissettii forest is a very dark and scary place lol.

But also Rubromarginata is great. Rubro grows incredibly fast. In tests it was rated the fastest spreading bamboo. And it grows very very tall but screens all the way down to the ground as long as it gets sun.

I'd leave an area large enough to mow between the properties to control it. A good 20 feet maybe. If it starts taking over his yard you might start a real war with them.

(do not get nigra or aurea in your zone)