Start New Perennials from Root Cuttings
Take root cuttings of most fleshy rooted perennials in late winter or early spring before growth begins. Wait until after the bleeding heart has stopped flowering and oriental poppies go dormant to make these root cuttings.
Start by raking the soil away from the base of the plant so that several roots are exposed.
Use a sharp knife to remove several roots. Cover the remaining roots and water the plant.
Cut the roots into 2 to 3 inch segments. Lay them on a well-drained potting mix, moist sand or other rooting media. Cover the roots and keep the rooting media moist but not wet.
New growth should appear in several weeks. Young plants can be moved into the garden or container in a sheltered location.
A bit more information: Division is the easiest way to start new plants. Simply use a sharp spade to dig the plant and lift it out of the ground. Use a sharp linoleum knife, drywall saw or two garden forks to cut the original plant into several small pieces.