You could go with foliage color. Yucca and Sedum. The Sedum you do get color foliage when your other plants are blooming and the flower late summer/fall when your other plants are not blooming in your dry bed,
Sedum would be great for dry no water plants.
Sedum, Spring bulbs and daylily bed.
Daylily with a Sedum Frosty Morn as White and green tall sedum that blooms pink and white August/Sept.
In this bed I have cactus, and daylilies and a Yucca Color guard the Yucca is color all seasons.
