By September the spartina behind Tybee shifts from green to a slow gold, and the creeks threading it fill and empty twice a day without asking anyone. Southern Marsh Lawncare works the high ground beside all that — mowing, edging, string trimming and seasonal cleanups on lots where the lawn ends and the marsh begins. Salt, sand and tide set the terms out here, so cutting height and timing matter more than the machine. Warm coastal weather keeps grass moving nearly all year, with the quiet months given over to trimming and clearing. The line that matters is that boundary, kept crisp: cut lawn on one side, wild marsh on the other.