My cat chews up some of mine and also my neighbors' plants. How can I break her bad habit before my neighbors get mad?
Pet stores do sell "Pet Grass" which gives them something to chew on (or grow your own). You can put it near their food and hope that it satisfies their desires. You will get more mileage out of your pet grass if you keep it watered.
Also, related to this. A surprising amount of house (And outdoor) plants are toxic/poisonous to cats to various degrees. If you have pets, please check this reference of toxic plants before introducing those plants into your yard or home.
There are products out there that can be sprayed on objects (plant, furniture, etc) that will add a bitter taste when licked/chewed on. This might be enough of a deterrent to stop your cat from chewing on the plants.
In the past when I have used it outside I applied it every couple days to the problem spot and within a week my dog had stopped chewing on the trees outside.
I have lots of plants and keep them all behind closed doors so none of my cats can eat them. I do this for the benefit of the cats much more so than the plants.