When divided every few years, perennials benefit by becoming stronger and producing more blooms. Dividing perennials create more, smaller, clumps of the same plant. Even if more plants are not desired, perennials should be divided to rejuvenate old plants.
The first step to division is to dig up the plant to be divided. Wash a majority of the soil away from the roots so you can easily determine where to make the division. Some plants can be divided by gently pulling off sections of the crown, while other plants may require a sharp, clean knife to cut through the roots. Do not take too many divisions from one plant, as each section must have enough healthy roots to sustain growth. If any part of the root looks dead, damaged, or diseased, trim it back to healthy white tissue.
As a general rule, plants that flower in the spring and early summer should be divided in the fall. Plants that flower in summer and fall should be divided in the spring before new growth is too large.
PLANT | BEST TIME TO DIVIDE |
Aster | Spring |
Bleeding Heart | Spring or Fall |
Campanula | Spring or Fall |
Chrysanthemum | Spring |
Columbine | Spring |
Coreopsis | Spring |
Delphinium | Early Spring |
Echinacea | Spring or Fall |
Gailardia | Spring |
Geranium | Spring or Fall |
Hosta | Spring or Fall |
Iris | Late Summer, Fall |
Lily | Fall |
Monarda | Spring |
Oriental Poppy | Summer |
Phlox | Spring |
Rudbeckia | Spring or Fall |
Scabiosa | Spring |
Sedum | Spring, Summer |
Vinca | Early Spring |
Yarrow | Spring, Late Summer |
Yucca | Spring or Fall |