Great advice from Paul, as always, and I want to add, the rhizomes (base of the iris) need to be sitting so the top is above ground. My granddaughter says like a duck on water. They won't flower if too deep.
If possible you could take a photo of the existing ones for us, and maybe we could see something else to address?
But, welcome. You'll definitely learn how to grow good irises from the posters on here.
