Cat repellant plants

Ok, so there is teh drama going on in my neighborhood. Long story short, evil neighbor is trying to trap cats. Because they are pooping in her yard, and her children play with the poop. Ignoring the idiocy of why she isn't watching her children combined with why her old-enough-to-know-better/old-enough-to-listen-when-you-say-eww,icky,yuck,no, children are playing with poop, combined with the whole cats don't like to poop in yards, dogs do, let's go ahead and give her the benefit of the doubt and say she's just that scared/allergic/harbors an unrelenting hatred for all things fuzzy.
Does anyone have any recommendations for plants or ideas for repelling cats? I've read citrus peels work wonders, to try the herbs rue and lavender, sprinkle ground black pepper and crushed red pepper, and to lay down cedar mulch. I'm quite willing to purchase plants or cedar mulch for her (she's a renter, so I doubt she'd want to try buy them herself) if that will help. I want peace in my neighborhood, damn it. -_-
I'm sure there are others here who have had this issue! What have you tried, and how did it work for you?