Replicating a favorite rose bush can be done by taking a cutting from the bush, and then starting a new plant from the cutting. Choose a healthy stem for your cutting, one with a rose growing on the tip. Below the flower, at least two five-leaf-leaflets should be attached. Wait until after the rose has come to full bloom on the selected stem before taking the cutting.
Sanitize a pair of cutting sheers. Before cutting the bush, the sheers should be clean. You can do this by washing the sheers in hot water and soap and thoroughly drying to avoid rusting.
Cut the stem from the bush, moving down about 6 or 7 inches. Cut diagonally across the stem.
Cut the rose from the top of the stem. Cut diagonally.
Snip off all but the top two five-leaf-leaflets growing on the cutting.