Posted: 12/04/2015 at 09:14
janebal, Do what you were originally going to do. If you find it doesn't work, do something else next year. There are no hard and fast rules, there are opinions, some more informed than others. A natural pond, where the irises naturally grow, has ordinary soil all around the edges and on the bottom. Natural ponds find a balance.
Do a bit of experimentation and report back with your opinion.