re: Help with getting rid of elephant ear plants

I did this with banana plants and also Elephant Ears and that is to cut them down to ground level and EVERY time green growth shows up, take a shovel and cut it off at, or just below ground level.

If no photosynthesis occurs, the roots will eventually die.

Now, if your neighbor has them, that's a different story unless you can dig a trench along the fence and put down some sort of barrier to keep the roots from invading your yard.