Clumps of iris should be divided periodically to keep them healthy and blooming. If you notice the roots becoming crowded and the tubers heaving out of the soil, then it’s probably time to thin them out. In Texas, the ideal time to divide irises is September, but October will also work. The goal is to get the new divisions in the ground and get new roots growing before the onset of winter.

If you’ve never divided iris before, keep in mind that iris plants grow from rhizomes, not bulbs. A rhizome is a type of stem that grows horizontally instead of vertically. Usually, these stems are below the ground, but some species of iris produce them at the soil surface. Those fleshy, tuberous parts that look like roots are actually stems. The leaves of the iris grow up from the top of the rhizome and the roots grow down from the bottom.

Once the irises have been divided, you can replant immediately or save the divisions for later planting. When replanting, make sure not to plant too deeply.

Here is the link to a great video that shows the proper method for digging and dividing iris: https://extension.illinois.edu/…/2021-08-20-how-divide…

For information on storing irises for the winter, see: https://travis-tx.tamu.edu/…/store-iris-rhizomes…/…