One of the most important methods for propagating plants at home is crown division. Herbaceous plants such as chrysanthemum, day lily, peony and iris can be divided by this method. Some woody shrubs that branch or sucker from the base can also be reproduced by this simple and reliable method.
As a general rule, plants that flower in spring and early summer should be divided in late summer or fall. Those that flower in summer and fall should be divided in early spring before new growth begins.
For crown division, carefully lift plant clumps and remove some soil from the roots. Then, cut the crown into sections with a knife (Figure 8). Individual shoots that contain roots may be used to form new plants, or if a larger plant is desired, several shoots may be left together. For your best chance of success in diving large, old crowns, discard the older, centre portions and replant the young, more vigorous shoots that have developed on the edges of the clump.
Shrubs may be divided in the same manner but when the plants are dormant. Because shrubs are often woody, they may need to be separated with a shovel or hatchet. Before planting, trim back the shoots and cut off damaged roots.
Plant crowns of many perennials may be cut apart to form new plants.