Bearded iris is a spectacular perennial plant that will beautify the landscape with its blooms and lush foliage. Bearded iris is prolific, and the roots will grow and multiply year after year. As a result, bearded iris plants can become overcrowded, resulting in slow growth and stunted blooms.To keep bearded iris blooming at its best, divide the plant before it has a chance to become overcrowded, every two to four years.
Insert a garden fork into the ground about 6 inches from the bearded iris. Rock the garden fork back and forth to loosen the roots. Continue around the circumference of the plant, then use the fork to lift the plant from the ground.
Shake the excess oil from the clump to make it easier to see the natural divisions. Cut the bearded iris apart at the divisions. Discard the old, unproductive center of the plant, along with any sections that look decayed. Trim the foliage down to about 4 inches using kitchen shears or pruners,
Soak the divided plants in a bucket with a mixture of one part household bleach and 10 parts water. Remove the bearded iris after 20 to 30 minutes. Place them in a shady spot to dry so the cut sections can heal.
Return part of the bearded iris to its original spot, then dig a hole in the newly-prepared spot just deep enough to accommodate each bearded iris. Form a small mound of soil in the bottom of the hole, and spread the roots out evenly around the mound. Fill the hole with the reserved soil, and tamp the soil down gently.
Water the soil thoroughly immediately after planting. Give the bearded iris about 1 inch of water every week during the growing season after planting.
Feed the bearded iris immediately after planting, using an all-purpose, water-soluble fertilizer that has been diluted to half of the strength recommended on the package.