Dig a hole about six inches deep and wide enough to accommodate the rhizome and its roots. Build a small mound of soil in the bottom and place the rhizome on it, spreading the roots carefully. Adjust the height of the mound so that the rhizome is just beneath the soil's surface. Fill in the hole and water. Bearded irises should be spaced 12 to 18 inches apart.
Ample moisture is required in spring when flower buds are developing and during flowering.
The most serious bearded iris pest is the iris borer. It overwinters in the egg stage attached to leaves. The eggs begin to hatch in late April. The tiny caterpillars crawl up iris leaves and begin chewing and mining their way down within the leaf fold, eventually reaching the rhizome. Once in the rhizome, they continue to feed, sometimes reducing the rhizome to a hollow shell.