Assuming you are referring to Dietes or what are most commonly called African iris, they will most certainly not be winter hardy for you. They are evergreen in their typical environment and form large clumps (as you can tell from their height) and I would think not the easiest plant to accommodate indoors overwinter. Pot them up and store them somewhere with lots of light and where the temperature stays above 40F - a greenhouse would be ideal. Bloom time in their normal zones is quite lengthy, often producing flowers throughout the growing season, although each flower lasts only a single day.

In my zone, they are only marginally hardy and even in a protected microclimate, didn't thrive. Only a couple of blooms in the 4-5 years I had them before they gave up the ghost.

Thank you for the response. I potted the iris up, and brought it in for the winter.