Division is one of the three main methods used by gardeners to increase stocks of plants (the other two are seed-sowing and cuttings).
Division is usually applied to mature perennial plants, but may also be used for shrubs with suckering roots, such as gaultheria, kerria and sarcococca.
Additionally, plants that are too close together will stay damp longer due to poor air circulation.
Use a shovel, gardening shears, or knife to physically divide the plant into multiple "divisions".
The division will have trouble staying rooted if the ground is freezing and thawing frequently.
A plant should be divided when it starts producing fewer flowers, has a lot of dead growth in the center (crown), or cannot support its own weight.