"Spreading groundcover type perennial plants are great to fill in cracks and spaces in paving," writes Marie Iannotti. "Plants like spreading sedum and creeping thyme are favorites because they can handle some foot traffic and neglect." About's Gardening Guide offers many more examples of perennial groundcovers in this photo gallery. Check out her groundcover photos for some ideas for your own yard.

_{Photo of Scotch moss groundcover ©2006 David Beaulieu (licensed to About.com)}