The best time to move and divide irises is late summer or fall. Dig up the clump, break off the side roots, and toss out the old tired center of the clump. You can shorten the long grassy leaves to about six inches to make moving easier. Replant in full sun in well-drained soil. Do not plant too deep—just below the surface of the soil. You should be retiring about one third of the clump, the oldest center section. Save the side growth and divide up into smaller sections. Get ready for great blooms next spring. Keep growing, Marianne Binetti