Mexican bush sage (Salvia leucantha), is native to Mexico and Central America, and therefore isn’t in our Native Plants Database which would include information on growing conditions. The link above indicates that the plant prefers full sun, and evenly moist, well drained soil. Sand is certainly well drained, but probably could stand some amending to improve moisture levels.
This link has a video about pruning that could help improve your plant's appearance.
Try to hold off on ripping it out until after it blooms in the late summer. This information from Floridata might give you some hope.