Iris flowers, in late spring or early summer, form three to five buds on a stalk growing up from the rhizomes. The buds often open in succession, with the last frequently opening as the first and top-most bloom fades. Care of the iris after it blooms is simple most years. However, as the rhizomes multiply, it is necessary to divide and separate them on a regular basis to ensure continued flowering over the years and to multiply the plants.
Remove dead leaves in the fall or in early spring before plant growth. Clip dead leaves with shears close to the rhizome, rather than pulling them away.
As blooms fade on the stem, clip the buds off. The plant will put its energy into growing the rhizomes, rather than producing seed.
Lift and divide the rhizome clumps when the plant becomes over crowded. Reduced flowering is a good sign the plant needs dividing. Divide rhizomes after the last bloom has faded.
Keep the plants watered throughout the summer, which helps the plant recover the energy spent producing flowers.
Lift the rhizome clump with a garden fork or spade. Be careful not to damage the rhizomes. You should be able to pry them out of the soil with little effort if you loosen them on all sides before lifting.
Gently shake the soil from the rhizome clump, exposing all of the rhizomes.
Cut the rhizomes into sections, selecting plump, young and healthy sections for new plants. Each section must have leaves growing from one end. Cut the sections 3-4 inches long.
Trim the leaves back to 6 or 8 inches, forming a stiff fan on the end of the rhizome. This prevents moisture loss and uprooting by the wind.
Cut the rootlets on the bottom the sections back by half. Use care not to damage the root base on the rhizome.
Plant the rhizome sections after adding soil amendments. Only bury the bottom half of the rhizome, the top half should be exposed. Face all the fans in the same direction in a row.
Keep the plants watered throughout the summer. The rhizomes must grow again in order to produce flowers the following year.