When an Iris is purchased, it will be either in bulb or rhizome form. If the Iris is in bulb form, planting it is just like planting any other bulb plant.
Planting Iris bulbs should be done at a depth of about three inches, making sure that the bulb is facing pointed side up. Plant Iris in fall. It will be dormand in winter and grow the next spring.
When planting Iris in rhizome form, do not plant them too deep. The upper 1/3 of the rhizome should be exposed to the sunlight.
How to Plant Your German Bearded Iris Rhizome