The family of herbs known as mint, or lamiaceae includes kitchen staples ranging from basil and oregano to sage and rosemary. Mint flavour or aroma, however, comes from the true mints of the genus mentha. Of these, peppermint, also called mentha x. piperita, and spearmint, also known as mentha spicata, are the most familiar and serve medicinal, as well as culinary, purposes. The differences between these two plants determine how each can best be used.
In the Garden
To identify a mint already growing in your garden, try gently rubbing the leaves and sniffing your fingertips. Peppermint has a stronger, slightly more medicinal fragrance than spearmint does. Next, look for the purple tinge to leaves and stems characteristic of peppermint. Also note that spearmint tends to be shorter and have smaller, more wrinkled leaves. The edges of peppermint leaves, however, are more jagged. Though both mints spread easily, spearmint tends to be the more invasive of the two.
Spearmint and peppermint are the top two mints grown commercially. Because consumers prefer the cooling sensation of peppermint, more products are made from it. Peppermint dominates chewing gum flavour, which the USDA calls "the most [commercially] important use of mint." Though both mints are contained in medicines, toothpaste and mouthwash, peppermint is also chosen frequently for candies and liquers.
Despite peppermint's commercial popularity, spearmint, also called "garden mint," is the home gardener's favourite. Milder and coming in a range of varieties -- including pineapple mint, apple mint and curly mint -- spearmint mixes well with other herbs and flavours. Widely used in traditional cuisines around the world, spearmint freshens salads, roasted meats and grilled fish as well as cool beverages such as iced tea, mint julep and mojito. Chocolate desserts and hot tea are more appropriate for peppermint's bold taste.
Peppermint and spearmint are used similarly in both conventional and alternative medicine, Mainly, the two mints ease digestive upsets such as nausea and vomiting. The therapeutic properties of peppermint come from menthol, whereas spearmint's come from carvone. These active ingredients are derived from the essential oils found in the leaves of the plants. Menthol, the more potent of the two, also serves as an antiviral, anti-fungal and decongestant, and thus, peppermint has wider application. However, the milder nature of carvone makes spearmint a safer choice for children and more sensitive adults.