To care for irises, plant them in a location where they have access to plenty of water and sun. Fertilize lightly once a year, and divide rhizomes when they become crowded.Continue Reading
Irises bloom best in an area with at least six hours of sun per day, so select a sunny location where irises can be watered in soil that drains well. Soggy areas cause rhizomes to rot.
Fertilize with a low-nitrogen fertilizer after planting. Fertilize irises again every spring when the green foliage starts to emerge from the ground to give the plant food to make beautiful blooms. Add fertilizer according to package instructions. Do not over-fertilize as this can cause an imbalance of soil nutrients. Compost can be added in place of commercial fertilizer.
Irises may stop blooming if rhizomes get too crowded. When this happens, divide rhizomes in late summer when the weather starts to cool. Gently dig up the clump of rhizomes and pull them apart with your hands. Throw away any rhizomes without green stems as well as any that appear rotten. Trim leaves to 6 inches tall and replant healthy rhizomes in groups of three, 12 inches apart. Water and fertilize well after transplanting.