I doubt that it's rabbits - my parents' yard is full of wild bunnies in the spring and summer, and no one ate any of the roses! When pulling into the yard on a summer night, there'd be 20-30 white tails hopping over the brook into the woods!

Maybe a woodchuck? Any suspicious-looking holes in any bankings nearby? Or maybe you have tastier roses? Miss Hoppy eats lots of flowers - clover flowers and dandelion flowers are particular favorites!

Rather than a gun, I'd just put up a discreet metal/wire fence - like rabbit fence, right around the bush. They usually sell them painted green that'd blend right in.

As soon as the tulips even sprouted, back home, there would be bunny-nibbles on the leaves, and the small white fences went up around every small garden, and the veggie garden, too.

The funny thing is, no one here (just 45 miles from my parent's house) eats my tulips, and I know we've got wild bunnies, lots of squirrels, and raccoons.