Good luck with the neighbors but a screen of hedges won't help and in this case not even a fountain's noise will make a difference. Our neighbors kids will have very late night parties around the pool and it drives you crazy for years and we have shrubs, a loud spa everything but until we got these new low e windows it is now very quiet. That might have to be your solution.

I agree, a vine is not the solution for muffling noise, but if you still want a vine, Akebia quinata or Parthenocissus henryana will grow fairly well in shade.

wanda

A masonry house with double pane windows is the ultimate in internal sound deadening, as long as you don't need to open a window. Notice the sound walls built along urban freeways to protect subdivisions from the highway noise. They are also growing vines on those walls in some areas. Probably the creeping fig Ficus pumila will be the most tolerant of shady growing conditions. Al

I have been looking into 2 CA Natives that do well in shade. One is Oregon Grape and the other is Spice Vine. Probably won't cut down on the noise, but I am assuming you want to be able to sit out and enjoy your backyard. I would get an ipod or similiar and put on your headphones. A solution might be to tape them at there drunkest and loudest, then on one of there quiet nights...turn it up, so they get to here how dumb they sound! Some people, just love hearing themselves talk! I know my husbands has a couple of friends that seem to compete with each other, thinking each is more interesting when drunk then the other. Fortunately, I have just stopped planning BBQ's and inviting them over. I realize that is not an option for you, sorry!

I had a similar problem with the drunk, loud neighbors behind us, and their little (drunk?) barking dog too. I don't think a vine, a water feature, or a 20'wall will solve your problem. It is a sticky situation.
People that don't understand civility or how to be a good neighbors also don't know how to respond to polite requests. We were afraid that a visit by the police would only amplify our situation.
Sadly, there was a house fire about a year and a half ago, which left the house vacant. I think it was Karma for shooting out all our rear sliding glass doors while taking bb gun practice against the back fence one day.
It is very frustrating, and you shouldn't have to abandon your yard or wear headphones or fear retaliation for seeking peace and quiet.
I know that if they rebuild the house behind us, I plan to have a good talk with the owners of the surrounding homes to see if they would like to get together to discuss what we can do together to keep things pleasant.

Thanks for the suggestions. I'll try them. It just isn't fair that i cant sit out in my own yard which i have worked SO HARD to create these years. You are right that some people can't be approached. I'd be afraid they would throw poison over the fence for my dogs. I guess i'll just have to be patient and allow Karma to take over.
Thanks everyone, chris PS. i posted a while back about lawn substitute for dogs...wel the blustone pavers are gorgeous with the isotoma/elfinthyme/corsican mint/lime thyme in between. And smells wonderful when they go running around!