Iris plants are best cut back in the fall. Spent flower stalks can be removed in spring after the plants finish blooming, but the foliage should be left standing through summertime. ... Then remove the trimmed foliage from the area, rake away autumn leaves, and pull back any other debris covering the rhizomes.

When should I cut back irises?

In mid summer, when the plants begin to look ratty, cut all the foliage down by half to create “fans” of leaves. Always cut at an angle. At the end of the growing season, after the leaves have been killed by a few fall frosts, completely remove all foliage. Most of iris diseases overwinter on the leaf debris.

When should iris be cut back for winter?

It usually takes several weeks for iris leaves to completely die back. By early fall, the leaves are usually ready to be cut back, according to the Utah State University Cooperative Extension. Leaves should be cut back to about 6 to 8 inches above the ground. Then, wait until after the first hard frost.