Sedum (sometimes called stonecrop) is a hardy perennial that is a favorite with many home gardeners for its colorful fall flowers and ability to bloom almost anywhere--even in shady, dry areas of the landscape. There are more than 400 species of sedums, most of which are hardy in USDA zones 4 though 9. These cultivars vary widely. Some sedums act as a short, colorful ground color, while clumping sedums grow to 2 feet tall. Clumping sedums need to be divided every other year to look their best.
Divide the fall-blooming sedums in the spring after the ground has thawed to allow the root system to become re-established before blooming.
Look for sedums that are falling over or bare in the middle.
Dig up the entire plant. Trace a circle around the sedum about 2 inches from the edges of the stems, and dig along the line. Keep the root ball intact if possible.
Lay the sedum to the ground on its side and look at the root ball for division points. Sometimes you can see where the plant has already begun to split into two or three parts.
Place the blade of the shovel on the division points (or just in the center of the root ball if you can't see any obvious divisions) and press on it with your foot, slicing through the root ball. Each new division should have at least two stems, and each root ball should have healthy (not rotted) roots and fine root hairs, which are sometimes called feeder roots.
Plant the new sedums in holes as deep and wide as the root balls. Back fill the holes with the removed soil. Tamp down the soil and water thoroughly.