I have a huge catnip plant growing right where they can get at it, and they couldn’t care less. What they DO go batsh*t for are the one-gallon pots of ‘cat grass’ that I sprout for them...it comes up just a few days after it is sown, and the cats LOVE it. Keep the barf bucket handy, though...
If I grow them cat grass, I'll get another dog, and he can handle the clean-up. ;)
/johnny