Overgrown neighbor’s back yard – Rats

Neighbor has like 4 feet of grass/weeds/vines and trash in their backyard. It was no big deal until rats started spilling over and under the fence. I’ve talked to the owner and the renter already, but they only cut their front yard.

Are there any ordinances or a good path forward? I’m pro let people live how they want, up until it creates actual problems for neighbors. Luckily, we have a healthy colony of feral cats that are killing most of the rats before they make it to my house, but the number of rats is growing fast.