Thursday Tips & Techniques: Dividing Perennials

Written by Heleigh Bostwick    Thursday, 08 November 2012

The rule of thumb is that spring and summer flowering perennials should be divided in the fall and that fall blooming perennials should be divided in the spring. Some perennials are best divided in the fall, others in the spring. The rule of thumb is that spring and summer flowering perennials should be divided in the fall and that fall blooming perennials should be divided in the spring. Many perennials benefit from being divided every 4 to 5 years. Lamb's Ears, bellflowers, and yarrow should be divided more frequently, generally every 2 to 3 years. Others like chrysanthemums should be divided every year, and some plants such as peonies don't need to be divided at all. September is the recommended month for dividing your spring and summer blooming perennials. Flowering should be complete at this time of the year and after dividing, the plants can put their energy into developing their root systems and leaf growth. Check the weather forecast before dividing your perennials. Cloudy or overcast days are best. Light drizzle is fine too, but avoid days that are expected to be sunny and hot. There should be a reason to divide perennials as well--unless of course you're planning on sharing a particular plant with another gardening enthusiast--for instance plants that have become too large for the space they occupy and lack the room for proper growth. In this case you might see flowers that are smaller than usual. Another good reason to divide perennials is when you notice that the clumps have hollow centers or foliage at the bottom of the plant is dying or yellow meaning that it's probably not getting enough light.