The dune sunflower (Helianthus debilis) loves well-drained sandy soils, making it ideal for Southwest Florida. Mine are planted in full sun, which it prefers, as it flowers more. It is a fast spreader, 1-2′ tall with 3-4′ spread, according to the Florida Wildflower Foundation. We have some planted in a wishing well my husband built us. I planted five in the wishing well, more than a year ago, and now the sunflowers cascade out, flowing around plants surrounding the base.