Cut back the root system of the yucca in middle to late spring. Use a shovel or a flat-bottomed spade and place it on the ground at the length of the longest yucca spike. Plunge the blade straight into the soil as far as you can. Remove the blade by pulling it straight up. Repeat the process around the perimeter of the yucca to cut through the remaining long roots of the plant.
Locate the original cut line, or create a new one if it has filled in with soil, in early to middle fall to actually transplant the yucca. Then work your way around the circle again but lean back on the shovel handle to loosen the root ball from the soil.
Slide the shovel or spade into the soil under the root ball as far as possible and push down on the handle to detach the yucca from the soil.
Put on protective gloves and goggles. Lift the yucca from the soil by grasping it near the bottom of the plant. Carry it carefully to a new planting site that has full sunlight and well-draining, slightly sandy soil.
Dig a new planting hole that is the same width as the yucca and the same depth as the root ball. Settle the root ball into the middle of the hole and fill the hole in with soil
Water the soil to a 4- or 5-inch depth to soak the roots and assist the yucca in recovering quickly from transplanting.