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.
After planting iris in either bulb or rhizome form, the plants should be watered. The soil must be well draining, as the bulb and rhizome are both very susceptible to rot. The plants should also be in an area of full direct sunlight. If some shade is provided, the blooms will not be as large or last as long of a time. There are, however, some colors of bloom that will hold much better when given partial shade from the hotter afternoon sun.
Transplanting iris is a pretty straightforward process as well. It is very similar to the act of transplanting other plants, but there are a few differences that make it require more effort. Transplanting iris can be done for several reasons. The plants may not be thriving because they are too crowded. This can be alleviated by dividing the plants and moving them to different areas of the garden. Transplanting iris that are crowded is easy to do. First, the plants must be dug up, and soil washed off with a hose. The rhizomes should be divided in a way that each section has a fan of stems sprouting out, and a good amount of healthy roots. Once divided, the older sections of the rhizome can be discarded, as they will not flower as well as they used to.
Once divided, it is time for planting the separated iris plants. Follow the same steps as above in order to plant in the rhizome form.
Transplanting iris can also be done if they are not growing enough. This could be due to bad soil drainage or not enough sun. Transplanting iris to a slope will greatly aid in soil drainage. Iris that are not getting enough sun should be transplanted into an area of the garden or landscape that will provide direct sunlight for the entire day.