My dog never met a grass he didn't like (and I have a $898+ emergency vet bill to prove it
), but he leaves the irises and daylilies alone.
Editing to add that IF you have a pup or young dog that is teething, or IF you have an older dog who is a dedicated chewer, THEN I could see that maybe the dog might get it's mouth on anything and everything in order to satisfy that chewing urge. This is why you keep your dog well supplied with safe chewing alternatives such as bully sticks and rawhide squares. (Yes, Warp is a dedicated chewer and is kept well supplied.)
