Iris germanica, commonly called bearded iris, is hardy in U.S. Department of Agriculture hardiness zones 5 through 11 and may not survive temperatures below 14 degrees Fahrenheit. Iris germanica blooms in colors ranging from pink to blue to purple to yellow and generally flowers in the spring. Some new cultivars will rebloom in the summer and fall. Plant bearded iris rhizomes from July through September to ensure their establishment before colder temperatures arrive.
Choose a planting site that gets full sun and has good drainage.
Prepare the soil for the bearded iris rhizomes. Work a low-nitrogen fertilizer into the soil with a tiller or hoe. Use 1/2 lb. of 5-10-10 fertilizer per 50 square feet.
Dig a hole about the same size as the rhizome. Create a soil mound in the middle of the hole so that, once planted, the top of the rhizome will sit slightly above the surrounding soil.
Place a rhizome, roots facing down, in the hole. Spread the roots around the edges of the mound.
Backfill the soil.
Repeat Steps 3 through 5 for each rhizome. Space the holes 8 to 10 inches apart.
Water the rhizomes thoroughly.
Apply mulch if you are planting in the fall.