Answer: Bearded Iris (the most often planted in gardens) grow from rhizomes that continue to grow on both ends. The older center part sometimes produces foliage but doesn't always produce a flower stalk. Iris beds should be dug and divided when the plants become overcrowded. The first indication that the clumps are overcrowded is failure to bloom. Iris grow best in full sunshine, in rich, moist soil.
Early fall is the best time to dig and transplant iris. Use a garden fork to lift everything in the bed, then break off the growing ends of each rhizome and replant the ends, discarding the dead center. Prior to planting in the bed, amend the soil with organic matter to keep the plants happy. Place the rhizomes just 2-3 inches beneath the soil surface and space each rhizome 8-12" apart. Water the plants well after transplanting.
It isn't necessary to fertilize your irises, especially if you amended the soil prior to planting. If you decide to feed, use a general purpose 5-10-10.
Best wishes with your garden!
Q&A Library Searching Tips