Although the genus Mentha comprises more than 25 species, the one in most common use is peppermint. While Western peppermint is derived from Mentha piperita, Chinese peppermint, or “Bohe” is derived from the fresh leaves of Mentha haplocalyx. Mentha piperita and Mentha haplocalyx are both recognized as plant sources of menthol and menthone and are among the oldest herbs used for both culinary and medicinal products. Spearmint can readily adapt to grow in various types of soil. Spearmint tends to thrive with plenty of organic material in full sun to part shade. Peppermint grows well in nearly all temperate climates. Gardeners often grow it in pots or planters due to its invasive, spreading rhizomes. Peppermint leaves can be used fresh, dried, or frozen. They can also be preserved in salt, sugar, sugar syrup, alcohol, or oil. The leaves lose their aromatic appeal after the plant flowers. It can be dried by cutting just before, or right (at peak) as the flowers open, about one-half to three-quarters the way down the stalk (leaving smaller shoots room to grow). Some dispute exists as to what drying method works best; some prefer different materials (such as plastic or cloth) and different lighting conditions (such as darkness or sunlight).