Acorus or Japanese sweet flag is used along pond margins and at the edges of water gardens. It is a great foliage plant for shallow water and marshy areas. It spreads aggressively by rhizomes and will eventually produce a seamless turf, making a beautiful groundcover for the front of a bog garden. When walked upon, it releases a fragrance reminiscent of cinnamon.
A grasslike wetland plant, with graceful weeping habit and elegant fine textured foliage, Carex is used for borders, as an accent, in masses as a ground cover, in rock gardens, alongside pools or in a hanging basket where its lush golden foliage can spill over the sides.
Liriope is one of the best evergreen ground covers because it multiplies rapidly and is so tough it requires little maintenance. The two major species are big blue Liriope muscari and creeping Liriope spicata. Liriope muscari grows to about 12 to 18 inches wide clumps. Liriope spicata spreads rapidly by long, tough underground stems and is often used for lawn replacement and erosion control, though it can be invasive. Grown in deep shade or full sun, sand or clay, Liriope tolerates heat, drought and salt spray, provided it is in well-drained soil. Mow in late winter before spring growth begins at the highest possible cutting height and just watch it grow.
Ophiopogo, or Mondo grass, is an evergreen perennial that is actually a member of the lily family. A perfect low maintenance ground cover for shady areas, the dense foliage suppresses weeds and is an excellent erosion control choice.