When I had a larger lot like yours, I found two things covered a lot of territory but didn’t take much upkeep or water:
Coyote Brush
California Pepper Trees
Neither was here in 1540 probably, but when you get tired of trying to make things grow, want something that will do well and cover a lot of ground, these are the ticket. Just make sure you plant the Coyote Brush way far apart from each other, and the Calif Pepper Trees at least 100 feet from your house or any foundation (invasive roots).
