I have the same problem with a couple of mine, and all the others around it are blooming or getting ready to bloom! Don't get it lol They were all midseason bloomtime too.

How much mulch is covering the rhizomes? Is there soil also covering the rhizomes? Irises should not be mulched. You can mulch up to the rhizomes that should be exposed a bit, but they should not be covered.

Taken from the FAQ linked below:
Planted too deeply
Bearded iris rhizomes should be planted so the tops of the rhizomes are at or slightly below the soil surface. If planted too deeply, bearded irises will grow leaves but may not flower. Be careful, also, not to allow mulch to cover the rhizomes. Make sure any mulch is pushed away from the rhizomes.

Here is a link that might be useful: I have no bloom on my bearded irises. Why are they not blooming?

They need sun so if they are in the shade then they will not bloom. Get that mulch off of them. The rhizomes need to see the sun.

Besides the mulch & shade issues, if your plant is too young you won't get flowers this year. Was it a small rhizome when you planted it? Give it time.

And get it in the sun & clear off the top of thr rhizome as the others said ; -- )

The Iris that didn't bloom and I'm sure it must be because they are so crammed in with each other, and maybe planted too deep..I could really use the space right now for my garden phlox plants that I rec'd at a plant swap 2 weeks ago. If I dig the iris up or cut the fans down, dig them up and let them dry up and plant later. Does this make sense? What about the ones that did bloom..can I cut their fans back too? This is why I don't like bulbs, you need to wait till their leaves die down and they are so ugly. I have a lot of my WS newbies planted that are doing real well, but they are getting crowded out by the iris fans.