Huge Beds What (if Anything) Can I Put On Iris Bulb-beds To Make Them Bloom?

What (if anything) can I put on Iris bulb-beds to make them bloom? - huge beds

I have a large iris bed that my mother in South Carolina, there are almost 50 years in Ohio. I have recently begun to break the bed, such as roots and tubers were so fruitful that is protruding from the earth. I transplanted some of them, but still not the flower, so I must missing something on the floor. Is there anything I can lay on the bed of flowering to promote?