Hi beaded iris will grow in most soils, they prefer full sun, but if they are pink/white give a bit of shade.
they soil should have good drainage to stop the rhizome rotting, if the soil is clay put in some compost,bark chippings around the rhizome to help with the drainage.
I have some and they grow really well and are just in common garden soil with a bit of compost around the rhizome. They will naturalise over time and if they get too bif they can be dug up and the rhizome split into pices and planted again. Good luck.