The FAQ (link at top of forum page) addresses the causes and potential remedies of non-bloom in bearded irises.

I had planted some where they only got a couple of hours of sun in the afternoon and they bloomed once in 5 years. After moving them away from the trees where they would get more sun, they have bloomed every year now (for 4 years).

Bearded irises like the heat, as long as its dry too. Sounds to me like a combination of not enough light and clay soil is your problem. Irises like alot of light and well draining soil. You might try siberien irises or maybe i. foetidissima in those conditions and I'll bet you get better results. If you must have bearded irises try i. pallida, Flavscens or Indian Chief - all of which I have found will thrive and bloom with just a few hours of direct sun.

Mike

iris thrive in our climate, BUT they need FULL sun. clay is fine for them, they prefer it, but you gotta have SUN SUN SUN! move them to your sunniest piece of land, if they don't bloom next spring my guess is your just lacking the sunlight to make them thrive.

Irises often won't bloom the first spring after a fall planting. The ones your mother gave you might bloom for you this spring.

I thought I'd add that the best fertilizer for irises is one with very low nitrogen (first number should be low). Bone meal is a good choice. I also sprinkled epson salt around in my iris and daylily beds this year since it helps them take in the magnesium and sulphur they need to stay healthy and disease resistant. Since I live in Middle TN where we have a lot of warm humid weather, I will also begin a fungicide regimen in the spring to help keep my irises and daylilies leaf spot free. Good luck with your irises.

Cathy

My irises aren't blooming yet, except for the clump in nearly full shade. Go figure.

Here is a link that might be useful: Beauty of Gardening