Question: What are some groundcover plants that don't require much water?
Bearberry (Acrtostaphylos uva-ursi) is an evergreen plant that forms a dense mat 6 to 12 inches tall and 15 inches wide. Prefers full sun or light shade. Doesn't need fertilizer or clipping once it is established, but it is a slow grower and can be hard to transplant. Hardy to USDA Zone 3.
Creeping lily-turf (Liriope spicata) is a grasslike plant with evergreen foliage that turns bronze in the winter. Plants grow 8 to 12 inches high and wide. Prefers part or full shade. A tough plant that spreads by underground stems and can be very aggressive. Zone 4 to 10.
Violets (Viola spp.) can form an effective groundcover in partial shade. Foliage dies down to the ground over the winter. Forms colonies by self-sowing.
Snow-in-summer (Cerastium tomentosum) is a perennial for sunny sites. Grows under a foot tall. Spreads by underground stems and by seed if the spent flowers are not removed in summer. Spreads most quickly in cooler climates. Does not tolerate humidity or very hot summers. Zones 3 to 7.