Are squirrel's eating your flowers or digging up the soil? Many times they are just looking for the moisture in the plant, so make water accessible to them in a nearby bird bath. If they persist, try this homemade repellent:
Fill a saucepan 1/2 to 3/4 full of water and put it on the burner to heat. Chop two jalapeno peppers and one onion into small pieces and add to the pan and heat to boiling. Add a tbsp of paprika and a tbsp of cayenne pepper. Simmer for 25 minutes, then remove for the heat and let it cool.
Pour the mixture through a cheesecloth or strainer. Pour the strained liquid into a spray bottle. Spray this homemade repellent over your plants once a week. As an added deterrent, you can also sprinkle some cayenne and paprika around the base of the plant.