Some tips for transplanting irises are to transplant between July and September, cut back the leaves and lift the plant with a spade. When separating irises, divide the rhizomes with a sharp knife or pull them apart by hand.
Because irises prefer hot temperatures, the best time to transplant them is between late July and September. This helps prevent fungus infections on newly transplanted flowers.
Before digging up and transplanting the flowers, cut down the leaves to one-third of their usual size. This helps manage stress during the transplanting process and promotes root growth.
Dig up the root structure, called the rhizome, with a spade or garden fork. Use the spade or fork to carefully lift up the plant.
Often, gardeners can separate the rhizomes by hand to divide an iris plant. However, some rhizomes may be stubborn. In this case, a sharp knife can separate rhizomes from the main plant. When dividing multiple rhizomes, clean the knife with bleach in between each cut to protect the plant from diseases.
Before replanting the irises, rinse the soil off of the rhizomes. Check the plant for worms and pick off any that are present. Iris borers are worms that can destroy irises, so it is important to destroy them.
Always get rid of dead or rotting growths. This helps avoid damage.