The other day I heard the click click click of nails and saw a blur running across my driveway, approximately groundhog size. Next day I saw one grazing on my grass. I just put three chrysanthemum cuttings by my mailbox, and now about an hour later they're gone. Yesterday I noticed my chrysanthemums had been "pruned". I understand grandhogs are hard to get rid of, with two suggestions for discouraging them standing out - an electric fence or pouring male human urine into their burrows.
Just found a list of plants that groundhogs/woodchucks don't like: http://askville.amazon.com/list-annual-perennial-flowers-groundhogs-eat/AnswerViewer.do?requestId=2536759