About every three or four years iris need to be divided and replanted. You don't mention if this has been done, but if not, it is probably the reason why you got no blooms.
Wait until August or so and the leaves should be yellow/brown and dying back. Dig up the iris with a fork or pitchfork getting underneath the rhizomes. Break them up and discard any rhizomes that are mushy, dried out, or withered up. Keep only the new fresh looking ones. Cut the remaining foliage into 4-6" fans. Add some fresh compost to the iris bed and replant them so the tops just barely show. You may have too many so give some away to your friends.
You should find that next year you'll have plent of flowers.