Cerastium tomentosum (Snow-in-Summer) - Sheets of snow-white flowers smother this grounder's mats of silvery gray leaves early every summer. Widely adapted, it grows 6-8" high, spread 2-3' wide in a year. Use as ground cover, bulb cover, in rock gardens, for edging along paths, or between steppingstones. Not long-lived. Avoid extensive planting in prominent situations.