Garden perennials are generally considered to be relatively low-maintenance
plants, but there eventually comes a time when the gardener recognizes the need
for a bit of upkeep.
Fall is an ideal time to divide and conquer those overgrown perennials that
have become crowded and unruly. Moderate
air and soil temperatures now favor a quick recovery and healthy root growth
with a minimum of stress to the plants.
Herbaceous perennials such as coreopsis, chrysanthemum, daylilies, delphinium,
iris, lamb’s ears, penstemon, scabiosa, Shasta daisy, and yarrow benefit from
occasional division to reduce their size and stimulate fresh new growth. It’s also an inexpensive method of
propagating additional plants for your garden or to share with friends and
neighbors.
Select the plants to be divided and prepare them by giving them a moderate
pruning. Pruning reduces the amount of
leaf surface and limits transpiration, which will deprive the new plants of
needed moisture at a critical time. The
first step is to carefully dig around the plant to be divided, leaving as large
a soil ball as possible. Lift the clump
gently from the ground.
Next, divide the main clump into several smaller clumps along the obvious
separation points. Often you can gently
tease the roots apart and separate the clump into smaller sections. However, if the clump is seriously overgrown
and the roots are badly tangled, you should pry the roots apart using two
spading forks. Insert one fork into the
center of the clump, then insert a second fork back-to-back with the first and
gently separate the roots. Repeat to
separate further again.
Discard the older, less vigorous portions of the clump and save the newer,
healthier divisions for replanting.
Healthy roots should have a white, sturdy appearance.
Replant the newly divided plants directly into the garden. Prepare the area to be replanted by amending
the soil with compost or other organic material to ensure that new plants
become established quickly. Plants may
also be potted up into containers for sharing with others. Water plants thoroughly after planting. Follow up a week later with a light liquid
fertilizer application. Provide
protection from too much sun, wind, and extreme temperatures.