Daphne, I agree with the others, you did just fine by your irises
. I've only been amending the soil in areas where irises have already been growing for several years. These are areas where I had large clumps of noids that have been dug to make room for new varieties. They have been growing well there for years, but I felt like the soil may be somewhat depleted of nutrients irises like and I wanted to give the newbies a good start. In the areas of virgin soil where new irises are being planted, I'm adding nothing.