Planting iris plants is very easy to do, and can be a rewarding experience. 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 the correct way up. This should take place in the fall, as the plant will then become dormant for the winter and then grow in the coming spring.
Planting iris that are in rhizome form requires a little bit more effort. The rhizome should be planted at or near the surface of the soil, while the roots shooting off should be planted down much further. The best way to do this is to dig a trench and have a mound running down the center. Place the rhizome on the mound, and spread the roots down the sides. When planting iris in bulk, it is important to ensure that all the rhizomes are facing the same direction. This will prevent crowding in early years.