After you've cracked a couple of eggs to make breakfast, rinse out the eggshells to feed to your flowering bushes. Rinse the shells and microwave them on a paper towel or microwave-safe plate for about 3 minutes. This will sterilize the shells and make them very dry. Crush the shells with your hands, and sprinkle the powder near flowering bushes like rhododendrons and hydrangeas. Your plants will thrive from the calcium boost the eggshells provide.