When clumps of iris start elbowing each other for room, blooming might be affected. Dividing them allows your flowers to rejuvenate. Here's what you'll need:Garden forkGarden glovesPowdered dolomitic limeFertilizerShovelTrowel
When iris clumps get too dense, it's time to divide. Using a garden fork, dig deep beneath the clump and dig it up.
Pull the iris crowns apart, separating as many pieces as possible without damaging the roots. With rebloomers, the foliage should not be cut back after spring blooming.
Wearing gloves, sprinkle one cup each of dolomitic lime and fertilizer onto the soil. Work it well into the soil.
When replanting, dig a deep hole (8 inches or more) and angle the roots straight down rather than splaying them out. New growth will come from the heel of the crown, so face them accordingly.
Firm the soil around the rhizome and roots, then water the transplanted clump generously. If precipitation doesn't oblige in a week, water again, but don't overdo. Irises dislike overwatering.