Without the use of plant material; the irregular edges of this French travertine style patio may seem abnormal. Adding plant material softens and adds rhythm to the patio edge. Groundcovers such as Pachysandra (Pachysandra terminalis) and Irish moss (Sangina subulata) work well for buffering a hard edge and are excellent for shady areas. [USDA hardiness zone 5b, Ann Arbor, MI]