Keeping rabbits from eating flowers and ornamentals can be done but it can sometimes require determination. It may take a two-prong approach - exclusion and repellants.
An 18-inch high border fence of wire mesh (1-inch X 1-inch) will do a good job of keeping rabbits out. Combine with this fence, a commercial repellent applied to the plants and you will deter the feeding. Repellents will need to be applied on a regular basis, since they dissipate after a rain or high winds.
In addition, there are a few plants that rabbits would prefer not to eat, but rabbits will eat almost anything if they are hungry. If you go to the following URL: http://www.wildlifemanagement.info/files/rabbits_4.pdf , you will be able to see lists of plants that rabbits prefer and plants that they do not prefer.