Knowledgebase
Dividing Siberian Iris #935925
Asked June 17, 2026, 7:26 PM EDT
Lorain County Ohio
Expert Response
Hello Joseph,
Thanks for your question. There is a great resource from Iowa State University that discusses transplanting and dividing iris. Here is a link to that resource:
https://yardandgarden.extension.iastate.edu/how-to/transplanting-and-dividing-iris
For Siberian Iris, it says that the best time to divide is once the clumps are over crowded, if plant vigor declines, or if the clumps form solid rings with bare centers. If they've reached that point, then they can be divided in either the early spring or late summer. So, right now would probably not be the best time. In the early spring, you can divide them when the new growth has just started to appear. If you divide in the late summer, you'd probably want to wait till August or early September.
I hope this helps! Please let me know if you have any additional questions.