If you want a long-blooming, easy-care perennial to edge the front of a bed or border, try dwarf cup flower (Nierembergia caerulea), suggests Wes Brittenham, landscape designer for WaterWise Landscape in Albuquerque. "It flowers all summer, and there's no need to deadhead," he says.
Hardy in Sunset climate zones 8-24, N. caerulea 'Purple Robe' grows just 6 to 12 inches tall and wide. It is not invasive, has no significant pest problems, and usually gets by with a weekly watering, says Brittenham. "It's as perfectly behaved as you could possibly want."
Brittenham likes to mix it with other fine-leafed plants. In his home garden he pairs it with red-flowered Salvia greggii. Gaura and pineleaf penstemon (P. pinifolius) would also be suitable companions.