There's a difference between reasonable concern and going ballistic. Have they talked reasonably to you at any point, or have they just gone off? I would try to talk with them one more time to educate them a little. You could always put in bamboo barrier to make sure the rhizomes don't cross over into their yard.

If they have come on your property or sprayed anything on your property, and they aren't open to reasonable discussion, I would suggest you contact the local police department. One thing you might ask them about is whether it will help if you send the neighbors a certified letter advising them that a repeat of this will be considered trespassing which will be reported to the police. It might even be advisable for the police to pay a "friendly" visit right now to document the problem. I don't advocate warring with neighbors, but some types just can't be reasoned with.

P.S.: You should be happy to know that herbicides have little or no effect on bamboo. So, even though they've contaminated things with some poison, it won't achieve their objective.

In most places I've lived, if you have vegetation going over into another person's yard (like tree limbs or roots), they can do what they want with it on their side of the property line, but that doesn't mean they can force you to do something on your side. Even if a tree on my property falls onto a neighbor's property, it's not my responsibility unless the person has sent me a certified letter showing there was a hazard. I'm not an attorney, but I would think that they will have a hard time in court, especially if they can't show any damages. Do they actually have any bamboo coming up in their yard from your grove? Or do you know if the rhizomes have crossed over? And what is all this Internet evidence they have? Just because it's on the Internet doesn't mean that it's true or that it applies to your situation. They just sound like they have a hole in their lives that they try to fill with mean-ness. It's unfortunate, but it's probably time for you to consult a lawyer to get a reality check. I don't pick unnecessary battles, but I draw the line at someone trying to force me to do something on my own property, and I sure wouldn't let some neighbor force me to remove plants that are important to me. But that's me.

As they say: In the U.S. anyone can sue anybody else over anything, regardless of whether the case has any merit. I'm starting to believe that Britain has a better idea...you can sue anyone, but, if you lose, you pay their attorney's fees, too. That would choke off frivolous suits, like the one you're being threatened with. Keep us posted: I'm very interested in what develops. And good luck to you!

The big concern about the bamboo was the dead leaves it was dropping on their bark and rectangular rhodies moonscape. Yes, they have sheared their few rhododendrons into rectangles.

So, I too would like to hear how you fare.

So far I have dug the bamboo up as I don't love it enough to have to worry about what additional rudeness it might prompt. Plans call for a wall of conifers and/or broad-leaved shrubs between them and us.

What I'd really like to do is raise the height of the chain link fence to the maximum allowed, making it physically impossible to reach onto our property (at least the part beyond the fence).

But I'm not the only one that lives here. And I don't want to put a contractor in the middle of something.

When they moved in they put brown plastic slats through the chain links, without discussing it with us beforehand (same as with the mal-pruning and littering). When it was pointed out to them that the fence was ours, they replied that they thought it was theirs - and that was the end of it.

The male of the species also smokes outdoors and stinks up our entire back yard. He also has this high-pitched small blower he likes to get out during pleasant weather and use to pursue the scorched earth policy. It of course takes a long time to get every last little bit.