The long, sturdy stems of the Iris and its complex, mosaic blooms give it an air of tranquility and mystery. One look at a vase of Iris one is immediately transported to a quiet, sunny field caressed by a light breeze.
Temperature is key when storing and planting iris bulbs. Unlike other flowering bulbs--which are stored cold--iris bulbs are stored in heated rooms. The heat keeps the bulbs dormant, and once the time for planting comes, their warm slumber is broken with ethylene gas. This is just another way flower farmers mimic nature. Ethylene is already present in all plants as a hormone and acts to stimulate the ripening of your banana, the opening of flowers, or, in this case, the waking of dormant bulbs. But that's just the first step in planting. Second, the newly awakened bulbs must be cooled down, which encourages root development.
Once awake and cooled, the iris bulbs can be planted in fresh, fertile soil. Depending the season (as well as geographical location) iris can be planted in hoop houses (fall and winter) or in open fields (spring and summertime). What they need is sufficient sun during the day, without oppressive heat that can cause them to go dormant. From bulb to flower, it usually takes 2-3 months before irises are ready to be harvested.