Artificial plants and flowers are great options for those who don't have a green thumb. For outdoor decorating, it is best to look for artificial plants that are designed for outdoor display. These plants come from the factory with their foliage coated with weatherproofing. If your artificial plants and flowers are made for indoor use, they can be weatherproofed. Any spray fabric protectant manufactured for patio furniture will work. Once the leaves are coated, they will stand up to the worst the weather has to throw at them.
Dust loose debris off of the artificial plant. A hairdryer set on low is an efficient tool if you have an extension cord, or use a can of compressed air. For smaller outdoor plants, fill a large bag with 1/2 cup salt or cornmeal. Dip the plant in and shake it for 90 seconds. The salt and cornmeal will absorb all of the loose debris.
Wipe any clinging debris off using a cloth dampened with a solution of equal parts water and white vinegar.
Coat the plant's foliage with a protective layer of fabric spary. Coat the foliage according to the manufacturer's instructions. Allow the coat to dry and apply a second coat.