When and how do I cut pay for "pond" iris plants?
Answers: You can cut them back after blooming if you want, but Granny is correct - there is no obligation to do so. Just split the plants apart every 3 to 4 years (more often if they are in containers) and any replant, give away or compost your extra plants.
Hope this helps.
You can seperate them after they bloom, but in that is no need to cut them back.