So I've got a neighbor who's idea of a well kept lawn resembles the Amazon Rain Forest.  While that in and of iteself is not a big deal (your lawn, your choice), the rainforest has expanded into my lawn.

Now when I say expanded, it ate my fence (grew over and through) this spring.  While I am constantly trimming off their crap, is there anything I can do.  I hate being 'that guy' the jackass  neighbor, but this isn't hey you got a tree branch on property--its your jungle claimed 10 feet of my fence!  Do I have any recourse besides constantly trimming that crap back?  Every year it keeps coming back worse and worse.  Ironically we livel in Nazi-ville where I get fined for having a blade of grass next to my rose bush out front (FU HOA!!) but this is the back yard so no one see it but me.

edit:I should add my neighbor isn't that great a person (very stand off, actually wife is hoarder and my 18 yo is scared of her) we don't have a good relation, but we aren't trying to kill each other either.

Up next 300 Blackout, rabbits, and Hasenpfeffer recipes.....

Ask him if you can go in and cut it back. Explain your concerns thoughtfully. 

If that doesn't work, night vision/ghillie/water-balloons-filled-with-roundup.

Edit: just had a similar situation with pitbull destroying fence. Nothing worked until it got halfway through and I put a 12 gauge on it and told them "I will shoot your fucking dog if he comes through " 

They built their own fence inside their yard after that.

Get some plant/grass killer and spray it all over your fence. Assuming it is a wooden fence, it will stay on hi/her side.

Glyphosate concentrate. Available at Lowes/Home Depot.

Get the concentrate, put it in a hand spray (at about 10x as concentrated as the package says), and spray anything you want to stay dead for a long time.

Also works when applied directly to pets and small children.

Roundup

Works for most stuff. I had some sort of fucked up little bush that kept coming up in my flowerbed, Round up 2,4D, would burn it good, weedeater would beat it back, but it wouldn't give up.

I had some growth regulator leftover from work, poured a little on there. Stunted the shit out of it. You can permanently ruin stuff with it. It won't necessarily kill it, it will just constantly looked smashed and tiny. http://www.domyownpestcontrol.com/bnine-wsg-plant-growth-regulator-p-2277.html

We don't know where you live so the internets isn't going to be super helpful. If your city has a code enforcement group, I'd call them. They will tell you if any of your local ordinances can be of help. You live in an HOA, do your bylaws address backyard overgrowth?