Take cuttings from your yucca at any time of year, but try for December through May for best results. Since yuccas are warm-weather plants, planting new cuttings during warm weather will increase your chances of success. Choose a mature stem and trim the leaves off the base of the stem. Cut the stem off close to the branch from which it's growing.
Allow the yucca stem to dry out for up to seven days. Place it in a protected, shady pot. Watch the yucca cane for any signs of rotting. If it rots, cut another stem to use.
Plant the yucca stem root-side down in a pot filled with quick-draining potting soil. Put the pot in a shady spot, and water it generously to keep the soil moist. The yucca cane will root within four weeks, and can be transplanted outside or to a larger pot at that time.