Iris plants are perennial plants that bloom in the spring. They are often used for fresh, cut flowers. Irises should be planted during the late summer or early fall and in an area that gets full sun to partial shade. While there are many varieties of iris plants, including Bearded Iris and Siberian Iris, they generally can be grown in the same manner.
Check the soil. It should be loose and have a pH between 6.5 to 7.0. Use pH testing strips, which are available at your local home and garden store, to test the soil’s acidity. Add sulfur to lower the pH or lime to raise the pH, if necessary. Follow manufacturer directions since each brand is different. Also, if necessary, add peat moss, compost, humus or sand to help lighten the soil if it is thick and heavy. If growing indoors, an all-purpose potting soil will suffice.
Plant the root, called rhizomes, only deep enough to spread out the roots and for the tip to poke out of the dirt. If the climate is extremely hot, place an inch of soil on top. Plant multiple rhizomes about one-to-two feet apart. The closer together, the more you will have to thin it out in years to come since irises will multiply. If you are planting irises indoors in a container, plant the rhizomes about an inch under the soil. Place in a sunny area of your home, such as under a south-facing window.
Keep your irises well-watered by watering every few days. Be sure to water enough so the water has a chance to soak in before evaporating.
Fertilize your iris plants if necessary. You shouldn’t need to do this, but if your irises are not thriving, fertilize them in early spring with a fertilizer labeled 6-10-10. Reapply after the blooms have died off.
Cut foliage back only after the blooms have withered away. Waiting for them to turn brown will allow the roots to store the maximum amount of food and nutrients.