These unthirsty succulents, flowers, and grasses will thrive with little care — even on a roof
In the Southwest and Rockies, swap in Helictotrichon sempervirens (shown) for Libertia peregrinans.
Helictotrichon sempervirens: Thin, blue-gray blades of this Mediterranean grass grow in clumps that reach 2 to 3 feet tall and wide. Blond flower clusters form 2 feet above foliage in spring. Zones 1–12 and 14–24.