Plant library · Groundcovers
Cerastium tomentosum
Snow-in-Summer is a low perennial groundcover that makes a silver mat about 6 inches high and spreads to roughly 2 feet wide. White, starry flowers cover it from late spring into early summer, creating a bright seasonal layer without blocking views across the bed. Its low-water habit makes it most useful where the planting can stay open, sunny, and relatively dry.
Use Snow-in-Summer at the front of a sunny border, along a hot dry edge, or through the pockets of a rock garden. Its creeping mat can soften the base of stones, retaining edges, and dry banks while leaving taller plants visually dominant behind it. Give it a defined planting zone rather than mixing it into a tight, intricate border, so its spread has room to read as a continuous ground layer.[1][2]
Plant on 18-inch centers for a joined groundcover effect. Each plant can reach about 2 feet wide, so neighboring mats will meet and overlap as they fill in; reserve the full width along bed edges and around rocks rather than treating the plants as small individual tufts. Keep it off routes used for regular walking, and set it back from paths where feet are likely to cut across the planting.[1]
Place this groundcover in full sun with well-drained soil, especially where moisture does not linger after rain or irrigation. Dry, sandy, shallow, or rocky spots suit its intended role. Avoid low pockets, heavily irrigated borders, and other places where soil remains wet, since poor drainage can lead to root rot and a thinning mat.[1][2]
The main floral display arrives from late spring into early summer, when white flowers rise above the low silver foliage. Plan for it as a spring-to-early-summer foreground feature, with nearby planting layers carrying the composition later in the season. Removing spent flower stems can help keep the mat neat and limit self-seeding.[1][2]
Snow-in-Summer can be short-lived, with bare patches developing after several years, so avoid relying on a single uninterrupted planting for a permanent carpet. It can also be more troublesome in cool-summer areas where growth is especially robust, while hot, humid summer conditions may reduce its performance. Leave access for dividing, renewing, or reshaping the groundcover as needed.[1][2]
Editorial content updated 2026-07-20.