According to the Celsius product label written by the manufacturers: This product has been tested and can be used on the following types of turfgrass and their cultivars:
St. Augustinegrass including Floratam, Palmetto, Bitter Blue, Common, Amerishade, Raleigh, Sapphire, Delmar, Captiva. When used as directed on the product label, Celsius should not cause damage to established St Augustine grasses.