Fencing for Rabbits
Fencing is the most cost-effective solution. A 1-inch mesh fence of poultry netting (chicken wire will work but is not very durable) works well to protect gardens or perennial flower beds from rabbit damage. Bury the bottom edge of the fence about 4 inches below the ground to prevent rabbits from digging under it (but it can just be pinned on top of the soil). The buried portion can be splayed outward from the protected area to better prevent digging. Use a fence 2 feet high against cottontail rabbits. You can extend the life of the chicken-wire, welded-wire, or hardware-cloth fence by taking it down each fall and storing it out of the weather, but remember that the stems of woody plants may be susceptible to rabbit damage during winter months.
Repellents for Rabbits
Some repellents are more effective than others. BGR (Big Game Repellent), also known as Deer-Away, is one that works for true herbivores like rabbits, but it will need constant replenishment. Exclusion is certainly a more permanent solution.