you need to let them die back naturally. I leave mine in their ornamental pots/or in the ground in full sun [when we get any] so the bulb/corm can regenerate. I must admit I never lift them. Apart from yellow Iris danfordia they come back every year.

I agree, it's important to leave them be for awhile, until the green tops die back naturally. Keep it watered as well. The bulbs underneath are growing and multiplying at this time and storing up energy for next year's show. In the fall, you can transplant them or divide them.

Give them a good feed while the leaves are still green, to help build them up for next year. I find they keep better kept reasonably dry once they have died back.

Thanks for that everyone.