AnnCamp
Tall beardeds will usually bloom well and increase in the second / third / and even fourth year following establishment from rhizomes ( seed can take longer ). There is a substantial difference from variety to variety AND in the local environment in which the clump is growing. The more favorable for growth - the sooner you will need to divide. I usually wait and divide when the rhizomes start to get thick on the ground and density of fans is high. If you wait too long to divide the bloom will diminish - this is a telltale sign that you waited too long to divide the clump. Generally speaking it will be in the third or fourth year when dividing is necessary - iris is a perennial after all. Where you are located will make a difference, too. ( latitude ) Hope this helps.
irisman646