Irises are a beautiful and elegant perennial flower that can bring a splash of color to any garden. To ensure that your iris bulbs get the best possible bloom, they need to be planted in an area with at least six to eight hours of sunlight a day. In very hot areas, a little shade in the afternoon can help keep flower colors from fading in the heat. Additionally, it's important to provide good air circulation and fertilize your irises in early spring and after flowering.
Bearded irises need at least six hours of sunlight a day, and should be planted in an area with good air circulation to help prevent disease problems. It's also important to make sure that other plants don't shade your irises; they do best when planted in their own special bed. When fertilizing your irises, use a low-nitrogen fertilizer such as 6-10-10 per 50 ft2 (or 1 ½ ounce by 10 feet). During periods of drought, you'll need to water them deeply every three or four weeks.
At your local garden store, you'll likely find some iris bulbs or rhizomes for sale, depending on the season. Rhizome-type irises produce larger flowers and include bearded and beardless varieties, while bulb-type irises produce smaller flowers and are often used in rock gardens or in the front row of borders to provide early season color. Different species range from low ground covers, such as Iris cristata, which is only 6 inches tall, to some of the large Japanese irises that are 3 to 4 feet tall. If you're concerned about whether your planted iris bulbs are getting enough sun in Minnesota, you can inspect them for signs of iris borers.
The University of Minnesota Extension provides detailed instructions on how to identify these pests when inspecting your plants in spring and summer. To a certain extent, you can prevent future problems with iris borers by properly trimming and cleaning your iris plants in the fall.