Echinocactus grusoni
Golden spines cover this slow-growing native Mexican cactus that reaches 4 feet tall and 2½ feet wide. Small yellow flowers top the plant in summer. It's hard to beat a cactus for a drought-tolerant plant. Sunset climate zones 12–24.
Lewisia cotyledon 'Sunset Strain'
This bright-blooming evergreen from California and Oregon reaches a foot high and 10 inches wide. It’s great in rock gardens, but needs excellent drainage. Zones 1–7 and 14–17.
Nassella tenuissima
Wispy green blades form clumps reaching 2 feet tall and wide. This grass found in Texas, New Mexico, and Mexico develops blond summer flower heads. Zones 2b–24.
Sedum spathulifolium Cape Blanco
Sedums make a wonderful addition to any water-wise garden. On this adorable drought-tolerant plant, tiny blue-green leaves form tight rosettes on trailing stems. This low grower from California makes a great groundcover and looks a treat in rock gardens. Zones 2–9 and 14–24.
Lavandula multifida
Woolly silver foliage -- a plant's natural protection against drought -- covers these Mediterranean shrubs. The plants reach 3 feet wide and half as tall. Thin stems topped with violet blooms appear from spring into fall. Zones 16–24.
Libertia peregrinans
Thin, stiff orangey blades of this iris relation from New Zealand reach 2 feet tall and half as wide. Clusters of inch-wide white flowers bloom in spring and summer. Zones 8, 9, and 14–24.
Sedum rupestre 'Angelina'
Short chartreuse leaves grow on stems up to 6 inches tall. This succulent from Europe spreads freely, making it a fluffy groundcover or filler between other plants. Zones 2–24.
Sedum spurium 'Voodoo'
Small, rounded burgundy leaves cover this low-growing, quick-spreading succulent from the Caucasus. Tiny reddish flowers bloom in summer. Zones 1–10 and 14–24.
Salvia clevelandii
Drought-tolerant plants don't always have to be succulent. Purple-blue flower spikes rise above aromatic gray-green foliage in early summer. This sage, from Southern California and northern Baja, grows 3 to 5 feet tall, and 5 to 8 feet wide. Zones 8, 9, and 12–24.
Sempervivum
This European native, with gray-green, pink-tipped rosettes from 2 to 5 inches across, grows into clumps spanning 2 feet or more. Reddish flowers shoot from thin, 2-foot-tall stems. Zones 2–24.
Agastache rugosa
In the Southwest, swap in Agastache rugosa (shown) for Lavandula multifida.
Agastache rugosa: Stems of glossy green, licorice-scented leaves reach 5 feet tall and 2 feet wide. This perennial from Korea has purple-blue summer flowers that hummingbirds love. Zones 4–24.
Helictotrichon sempervirens
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.
Look up for low-water plant inspiration
Rooftop gardens face special challenges: Since they’re constantly exposed to direct sunlight and wind, they demand super-tough, drought-tolerant plants. So if you’re looking for plants that’ll grow well in arid ground-level landscapes, a thriving green roof would provide plenty of inspiration.
Especially when that roof belongs to the much-lauded Margarido House, the first residence in Northern California to earn LEED-H Platinum certification. For this Oakland project, landscape designer Lauren Schneider mixed California natives that thrive in hot, dry conditions with plants that evolved in similar climates.
“I love the juxtaposition of the coarser and finer plant textures,” she says. “And I like to use the foliage colors as streaks and splashes.”
Design: Lauren Schneider, Wonderland Garden and Landscape (510/836-3990)