How can you grow another rose bush from an old one?

You can grow another rose bush from an old one by taking cuttings. Choose a healthy stem that is about 6-8 inches long, ideally from the current season's growth. Remove the lower leaves and dip the cut end in rooting hormone. Plant the cutting in a pot filled with moist potting soil, cover it with a plastic bag to maintain humidity, and place it in a warm, bright location until roots develop.