Blossom rot?

I'm a relative newbie to gardening, so this might be a totally obvious question, but: What might cause my iris blossoms to curl up and get squishy and brown before they bloom? They are bearded irises (variety = ??? they were a freebie from a friend) which are sitting in clay soil which gets soggy when it rains. (They did, however, survive the winter and put out healthy leaves.) The first few blossoms were fine, then the stems fell over and later blossoms rotted before they opened. The first blooms occurred during a warm spell (upper 70s-80s), and then we had several days of cool rain (50s-60s). I don't see any signs of insect damage or fungus, although I might not know what I am looking for.

If anyone could help me with a diagnosis and/or treatment, that would be great!!! :)

Thanks lots
pam