"laurie (Mother Mastiff)" wrote:

Last year the iris bed (about 3 years old now and new corms added each
year)
bloomed PROFUSELY. I put some rotted chicken manure in their bed in
late
summer and mulched with pine straw. There was nly space to add two new
corms.

A master gardener I know says that most iris need to be divided every other
year in order to keep blooming. Perhaps your iris bed is too crowded?