AMES, Iowa – The best time to divide perennials varies with the different plant species. Gardeners can determine when to divide their perennials by checking When to Divide Perennials (RG 319), an Iowa State University Extension and Outreach publication.
According to Richard Jauron, ISU Extension horticulturist, perennials are commonly divided for three reasons: to control size, to rejuvenate plants and to propagate a prized perennial. Some perennials grow so rapidly that they crowd out neighboring plants in the flower bed. Others decline if they are not properly divided.
“This publication helps gardeners divide perennials at the best times for the best results,” Jauron said.