With their tall foliage and brightly colored flowers, day lilies have become one of the most popular perennial flowers in the United States. They are easy to grow and care for, but often become too large for the space where they were planted. It's best to divide and transplant day lilies about every three to five years to keep the plants thriving in their environment.
Select a site to transplant the day lilies. Be sure the location is large enough to accommodate the plants with room to grow. Choose a sunny location, as day lilies need at least six hours of direct sunlight each day.
Dig up the existing day lilies, taking care not to damage the roots of the plants. A trowel or a small shovel should be sufficient for digging. If your soil is very damp and loose, you may be able to use your hands once you near the roots.
Separate the clumps you want to transplant, using your hands or a sharp knife. Again, be careful not to damage the roots.
Wash the newly separated clumps gently to remove all the soil.
Allow the clumps to dry in a shady location. They will need to sit out at least a few hours, but it's also OK to let them sit out overnight.
Dig a hole in the site selected for transplanting. The hole will need to be wide enough to accommodate all of the roots without the roots being cramped or folded over. Also, it's best to plant the day lilies at the depth at which they were originally grown.
Place the clumps in the hole, allowing the roots to settle and spread out.
Replace the dirt, packing it down firmly to remove air bubbles. If air remains in the dirt, the flowers may not take to their new location and can die.
Water the plants thoroughly, letting the water seep down deep into the ground. For the first week to 10 days after transplanting, water the flowers daily so they establish their roots in their new location.