Native to Central and South America, the genus Tithonia is comprised of bushy plants with bright flowers that are related to, and reminiscent of, daisies. Perhaps the most distinguished Tithonia variety is Mexican sunflower (not to be confused with sunflowers in the Helianthus genus). The striking vermilion color of its flowers is hard to find anywhere else, so luckily it's easy to grow and thrives in hot, dry conditions.