Plant the iris rhizomes as soon as possible after receiving. If necessary, the bulbs may be stored in a cool (not below 32ºF), dark location in their original packaging. Keep storage to a minimum: at most 2-3 days. (Once the plants are in the ground, you needn’t worry about freezing temperatures, as the plants are winter hardy.) Choose a sunny location with deep, well-drained soil that has been enriched with plenty of organic material or composted manure. Supplement the soil with a low-nitrogen, high-phosphorus natural fertilizers such as bone meal. Set the rhizomes, roots down, at the surface of the soil. Leave about 25% the bulb visible above the soil; if they are set too deeply the resulting plants may produce few or no flowers. firm the soil and water well. Apply a layer of protective mulch around the plants. In spring, irrigate prior to blooming to establish the roots for the first season. Do not allow the soil to become soggy. Established plantings usually don’t require additional water unless the area is arid. After the blooms fade, cut the flower stalk back as far as you can, and cut the leaves down to 6-8 inches tall in fall. Iris plantings benefit from thinning every 3-5 years since some varieties may tend to crowd themselves. Lift and separate the plants 4-6 weeks after blooming and transplant with 12-24 inch spacing. Discard any weak or withered rhizomes.