Dividing daylilies is not a difficult task, though it does require precise timing. The best time to divide them is after they have finished flowering, typically in late summer but up to early fall. Daylilies are hardy plants and can not only withstand the maintenance but also need to be divided in order to remain a vigorously growing plant. Once a daylily has been in a garden for about four or five years and begins to crowd its space, it can then benefit from the dividing process.
Use a rake or hoe to gently remove any mulch surrounding the plant.
Score the area around the daylily clump with a sharp spade.
Place a garden fork into the ground beneath the plant and work to loosen the clump of daylilies. Take care to stay 6 to 12 inches away from the plant's base. Work the garden fork around the root ball until the roots become free.
Use the garden fork to lift and remove the rootball.
Place two garden forks back to back and insert them into the large clump. Carefully push the handles apart to separate the rootball and create two smaller clumps. Repeat to create additional divisions, if desired.
Create individual fans of daylilies by using your hands to tease the clump into a division with a single fan of leaves with a cluster of roots intact.