Dividing overcrowded perennials is a common practice performed by gardeners to keep plants healthy. The resulting smaller clumps can then be planted in other parts of the garden or shared with neighbours. Some easy perennials to start with include coreopsis, monarda, echinacea, columbine and goldenrod.
Fall is an ideal time to divide plants because the weather is cooler and more rainfall keeps the soil moist. However, some plants prefer to be divided in the spring and some prefer not to be divided at all. That said, if the plant is not in bloom and you provide proper aftercare, most plants can be divided at almost any time during the growing season.
General Guidelines
Here are a few general guidelines:
- Water the plants the day before to make digging and removal easier.
- To prevent the roots of the divided plants from drying out, have the new planting locations ready with the holes already dug and try to divide plants on a cooler, cloudy day
- Using a shovel, dig around the plant keeping approximately 10 to 15 centimetres away from the plant to get as much of the root system as possible.
- Use the shovel to gently lift the root ball out of the ground. Then gently place it in a location where you have space to work without disturbing other plants in the garden.
- Pull the root ball apart into multiple clumps. If the roots are fine and loose, you can use your hands. If the root ball is matted and dense, you may need a garden hand-saw or serrated knife to cut through.
- Each division should have at least three strong stems attached to the root clump.
- Plant the divisions in their new locations immediately, ensuring they are planted at the same depth they were growing.
- Fill in any spaces around the roots and gently tamp the soil to eliminate air pockets, then water well immediately. Water regularly to keep the soil moist (not wet) and adjust to account for any rainfall.
Protect Your New Divisions
Newly planted divisions can go through shock and looking limp or a bit pale is normal. Protect tender new divisions from the cold by mulching with 5 to 8 centimetres of woodchips and/or fallen leaves, ensuring the mulch is pulled away from the stems.
For more information on spring versus fall dividing and perennial root systems, refer to this factsheet. Note there are several types of root systems, and some perennials require special treatment when dividing.