Now Is the Time to Dig & Divide Iris
Iris need to be divided before they become overcrowded and bloom starts declining. Some varieties may crowd out others and disease problems will be aggravated. In the Midwest the best time to divide the clumps is 6 weeks after spring bloom or generally in July and August. The iris have now set the bloom for next spring and have reached a dormant stage. The new roots must also have time to get established before the ground freezes. If the weather is very hot and dry, you might want to wait until Sept. when the temperatures are cooler. If ordering new iris and they arrive on a hot day in July, just plant them in a pot with garden soil and replant in the garden after the weather cools. Clumps may be divided by removing older rhizomes from the center and leaving new growth or by digging the whole clump and replanting the largest and healthiest rhizomes. It’s nice to have 3 new divisions to start again by planting them in a triangle with the narrow ends toward the cent