Spring, to me, is a time of constant discovery, the joy of seeing new life pop through the soil surface. It is also a great time to evaluate perennial beds [and some woody shrubs] to see if their spread needs to be managed.
It is usually obvious when a plant needs to be divided, as it has either overgrown its intended spot; the center of the plant appears dead; or the clump is knotted with roots. These conditions can be detrimental to plants, so division is strongly advised.
Plants also may be divided to create more plants for other spots in the yard, but care should be taken to allow the plant to form a large enough clump first.
The key to correctly dividing plants is to study the root structure from above. Clumping perennials, such as hostas and daylilies, can be completely dug out of the ground so the structure of the root ball can be examined. Using a sharp shovel, knife, or even machete, execute a cut through the roots vertically, taking care to keep all elements of the root structure in the divided sections. If you wish to divide the clump into more than two sections, divide in half, and then divide again.
For perennials with dead centers, dig the entire plant. Cut the outer circle into sections to replant and discard the dead center. Plant new, smaller sections as soon as possible, making sure to match the soil level of the original plant.
For woody plants or vining ground covers, cut the root or stem connected to the parent plant with sharp pruners. Then dig out the child plant by digging around it, attempting to preserve any roots that might have formed.
It is not uncommon for the soil to fall away from developing roots. If this occurs, just bury the roots in its new location, and water frequently as it gets established.
Woody plants that are oversized for their new root structure should be pruned back to a more appropriate size, and some initial staking may be needed to keep them in place until roots develop.
Now is a great time to tend to overgrown perennials. As an added benefit, you can add new life to other corners of your yard. The process is simpler than you might expect, and the plants welcome the room to grow.
Jim Stendler is a University of Illinois Extension master gardener for Kane County. The “Learning to Grow” column runs weekly during warmer months of the year. Call the extension office at 630-584-6166 for more information. Feedback on this column can be sent to firstname.lastname@example.org.