Cut a 6-inch section from the new growth. Older woody stems do not root well. Remove any buds and cut the end on a diagonal. Make small slits in the bottom of the stem to encourage new roots.
Prepare a mixture of equal parts all-purpose potting soil and perlite and fill a 4-inch pot to within an inch of the rim. Some prefer moist sand, but the perlite and soil mixture is light and encourages rapid root growth. Water thoroughly to moisten the soil.
Dip the end of the rose stem in rooting hormone powder. You can purchase rooting hormone wherever garden supplies are sold. Tap to shake off the excess powder and plant to a depth of 2 inches. Firm the soil around the stem with your hands to provide support.
Place a dowel or small stick in the soil so it extends past the height of the cutting. Cover with a gallon size plastic storage bag. Poke several holes in the bag to allow air to circulate. Place in a sunny location and keep the soil evenly moist. Roots will form in four to six weeks.
Monitor the cutting closely for signs of excessive moisture. Open the bag to allow moisture to escape and to increase air circulation if necessary. Remove the bag once the new leaves begin to form.