Thanks for writing. Unfortunately, a fence is the only tried-and-true way of keeping rabbits from eating your plants. You can try repellents; there's a wide variety on the market under brand names such as Rabbit Stopper, Liquid Fence, and Shake Away, though you may have to try several before you find one that seems to work reliably for you.
Otherwise, how's your lawn? Encouraging the growth of clover (a rabbit's favorite food) may also help. If you have clover in your yard, the rabbits often prefer it over your flowers. (Or at least that's my personal experience; I actually spread clover seed in my lawn to keep the bunnies out of my flowerbeds at home.)
---Justin, Senior Garden Editor, BHG.com