Iris corms tend to be late bloomers
Question: Last fall, I planted about two dozen iris corms. I followed the directions explicitly. All the plants appear to be healthy, growing green and straight but no blooms! I was advised that they need greater sun exposure. I planted them in an interior courtyard that has sun and shade. Some of my plants were in a planter, so I moved them to a southern exposure but they haven’t bloomed. I have the same problem with some day lilies I purchased in Las Vegas: green, healthy, lots of leaves but no flowers.
Two thoughts come to mind. In many cases, an iris needs a year to get established before it will bloom. Much depends on the size of the rhizome that was planted and how it was planted.
Sometimes, late-spring freezes can interrupt a flowering cycle, too. Give them another year to get established, and my guess is they will bloom nicely. Try not to overfertilize them or they may tend to be juvenile and grow leaves with no or few flowers. Fertilize them after blooming rather than before.
Bob Morris is an associate professor with the University of Nevada Cooperative Extension. He can be reached at morrisr@unce.unr.edu or 257-5555.