Calla lilies aren't true lilies but instead belong to the plant group Zantedeschia. Native to Africa, these plants sprout from rhizomes in the summer to develop into flowering herbaceous plants. Calla lilies grow to almost 3 feet tall and produce funnel-shaped flowers that are sometimes fragrant. Over the seasons, calla lily rhizomes propagate and pile upon one another underground, creating a crowded situation. This subterraneous clutter can cause your calla to stop blooming, letting you know that it is time to divide and transplant it.
Divide your lilies in late summer, after their blooming period and before their dormancy.
Dig around the base of your calla lily with a spade to loosen the soil. As you move in a circle around the plant, push the blade deeper into the ground until you reach below the cluster of rhizomes.
Lift the plant out and lay it on the soil's surface in the shade.
Separate the rhizomes from one another by cutting them with a garden knife. A rhizome is a thick stem that grows underground. Roots sprout from these stems. Calla lily rhizomes look a little like pieces of ginger root. While you don't need to separate them exactly at the point they connect, you should divide them so each piece has roots growing from it.
Count how many potential new plants you have after you finish cutting. The total tells you how much planting space you need to prepare.
Prepare an area to accommodate your calla transplants by incorporating 2 inches of compost into a site that receives full sun or partial shade. Keep in mind that each rhizome needs at least 6 inches of space to itself.
Rake the planting bed to a smooth surface and make 2-inch-deep furrows with a hoe.
Place your calla lily rhizomes in the furrows 6 inches apart. Back fill them with topsoil.
Irrigate the bed evenly immediately after transplanting your calla lily divisions. Apply as much water as it takes to keep these plants always in moist to wet soil in your region's climate.
Divide your calla lilies in the fall. Transplant them at the same time if you live in a mild-climate area where the rhizomes overwinter outside. In other zones, store the divisions until summer. Allow them to air dry and keep them at a temperature of 50 to 60 degrees Fahrenheit.
Calla lilies are poisonous. Keep them away from children and pets.