Peppermint (Mentha x piperita) is a native plant of England and a member of the large mint family. The herb is easy to grow, and it is used for cooking and for medicinal remedies in cultures around the world. Peppermint plants are propagated with cuttings and do not grow from seeds, which are sterile. If you see a packet of peppermint seeds, cautions Dorie Byers in “Herbal Remedy Gardens,” it is probably not peppermint but another nonsterile variety of mint.
Use a sharp scissors to take 3-inch-long softwood cuttings from the plant during the summer. Measure from the stem tips. Cut the base at a 45-degree angle. Softwood cuttings are succulent current-year growth that is not yet firm.
Fill a medium-size pot with well-draining potting soil. You can make your own growing medium by mixing together equal parts of peat and perlite. All mints grow best in highly fertile, well-draining soil, with a preferred pH of 6.0 to 7.5.
Water the soil in the pot well a day before planting and let all the water drain.
Press cuttings 1 inch deep into the soil and firm the soil around each cutting. Water well.
Place the pot in a warm, bright area with a temperature of 50 degrees Fahrenheit or above. Keep out of direct sunlight. Do not water again until cuttings are rooted and have started to produce some growth.
Transplant the cuttings into a permanent spot in the garden once they are well established. Select a partially shaded spot for growing mint or a full-sun site that receives some hours of shade every day.
Pick and use peppermint leaves as soon as foliage is mid-sized. The best time is before the stems start to flower, as recommended in "Margaret Roberts' A-Z of Herbs." Cut stems from the side of the plants to keep growth vigorous and help the plant spread.