Baccharis dioica, known as hammock groundsel, was at one time found in South Florida but is now believed to be extirpated in the wild in Florida. It is also native to the West Indies and southern Mexico. Hammock groundsel produces clusters of fragrant white flowers with distinctive yellow stamens from August through September. A member of the Aster family, it produces flowers that attract several kinds of butterflies, including Cassius blue and hairstreaks. This shrub grows 3 to 6 feet tall to form a nicely rounded, dense screen.