I just cut back about 1/2 of our irises on a hillside and just saw an article that I may be cutting them back too much. I thought you could cut the leaves back to 1 inch or so when also digging out and transplanting some of the rhizomes. Sharron Lee August 8, 2016 Kenmore, WA 98028 email@example.com
Cutting Irises Back
Iris plants are pretty darn tough. Cutting to 1 inch is severe, however. I try to lift, divide and transplant soon after blooming is over and cut leaves to 9 inches. In general, however, you should leave the leaves intact until they naturally start yellowing in fall. As with spring bulbs, the plant needs those intact leaves to nourish the rhizome (tuber) for next year's blooms. You haven't killed your irises and new leaves will emerge once the plant roots get established. You may have fewer blooms next spring. Fall is a good time to transplant because even after leaves die back, roots continue to work until the ground freezes.