Dividing perennials is a great way to encourage new growth in your plants.  This process will also produce additional plants which can be installed in your landscape.  At some point, most perennials should be divided to spur new growth.  The frequency and timing of dividing perennials depends on the plant.  There are also other factors as the plant size and health that should be considered prior to dividing perennials.  In order to get the most out of your plant, make sure your plant is healthy first.  Healthy plants should be divided at the end of the growing year or before the start of the next growing season.  The healthier the plant is, the faster that the plant will recover.  Healthy plants will transplant and divide better than weak plants.  If you have struggling plants, it may be beneficial to wait a season before dividing them.  It is important to keep in tact as much of the root system as possible.  The more roots that are attached to the plant, the quicker the new plant will recover.  Having more roots allows for more nutrients and water to be absorbed by the plant.

Dividing Perennials

Dividing perennials in the fall and spring.

Dividing perennials when cooler temperatures are present will help keep the plant from drying out as fast.  If you are not planning on replanting your perennials right away, it is important to keep the roots moist.  Watering the roots frequently while they are exposed will help ensure that the perennial is getting adequate moisture.  The amount of plant division will depend on the size of the existing clump.  A root clump that is a foot round should produce at least 4 good plants.  Flowering plants will require more attention.  If you choose to transplant perennials when they are blooming, make sure to keep your new plantings well watered.  Leaving exposed roots out of the soil for a prolonged period of time while the plant is blooming, may cause the flowers to die or may cause wilting of the plant.