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Herb of the Month

Peppermint and Spearmint: Mentha Piperata and Mentha Spicata

No child in my day could possibly confuse the red and white striped peppermint candies with spearmint, which was usually green. We all knew our toothpaste and chewing gum flavors. But what were the plants whose essential oils gave us those flavors? As an adult, I've enjoyed fresh mint in iced tea, greek salads, and Indian raita or green chutney, and I've found especially wonderful dried forms of the herb for tea. But until recently, I've wondered about the medicinal and nutrient values of this prolific summer herb, and I've never been really sure which mint was which and why.

There are about twenty species of mint growing world-wide and many transitional forms, hybrids, and regional variations. The nursery featured some of these hybrids--like pineapple mint (with lovely dappled white and green leaves) and apple mint with silky-haired, almost furry leaves). It also had other members of the Labiatae (or mint) family--like "catmint" (catnip), horsemint, lemon balm, and pennyroyal--which are not true mints but are fragrant and energetic. All plants in this botanical family have distinctively squared off stems with leaves arranged in pairs opposite each other; most are aromatic.

Three mint species are common in gardens (and have also escaped as "aliens" into the wild, moist meadows of New England). These include Mentha crispa, or curly mint, whose rounded leaves have frilly, shaggy margins; as well as our two herbs of the month, Mentha piperata or peppermint, literally "peppery mint," and Mentha spicata, or spearmint, literally "spiky mint."

Like the others, the two best known mints have vigorous growth habits (with underground stems carrying start-ups of the plant in all directions) and aromatic leaves that bear a volatile oil (containing menthol) in tiny surface dots. Both have small whorls of tiny pinkish-lavender flowers blooming in August. Spearmint flowers are arranged a little more like spikes; peppermint's are a little more like interrupted spikes, but the differences are slight. The differences you would notice are in the leaves: spearmint has vivid green leaves with pointy tips and crinkly surfaces. Each leaf seems to grow right out of the stem, whereas peppermint leaves each have their own short stem and are smooth, slightly less angular, and often tinged with dark purple. Peppermint stems are often dark purple, too, whereas spearmint's are always green. (Apparently there is also a light-colored variety of peppermint whose oil, though less plentiful, has a more subtle flavor and brings a higher price.) Spearmint seems to be the most common in gardens, often taking over from other plants, and there seem to be several varieties of spearmint (I have two strains in my own garden, each with its different habits.)

Of course the big difference between the two mints is in the taste. Spearmint is hard to describe. It's minty, but also you know you are tasting a green plant. Peppermint has an otherworldly zing. As an old Encyclopedia Britannica puts it, a "powerful aromatic taste followed by a sensation of cold when air is drawn into the mouth."

These two mints have slightly different properties according to the many healing traditions in which they have figured. Many herbalists use the oils or strong infusions of dried mint to treat the onset of colds and flu by promoting sweating and reducing fevers. (Spearmint is supposed to be a little better for lowering a temperature that has already risen, whereas peppermint is a little better at resolving phlegm and opening the sinuses.) Both herbs are frequently used to settle the stomach and stimulate digestion--as in "Grandma's Tummy Mint Tea" (one source says they help the stomach and liver produce more enzymes to aid digestion). Both mints also assist in reducing infection and inflammation (for instance, in urinary tract infections).

In addition, peppermint supposedly stimulates nerves, promotes clear thinking, and relieves vertigo and migraine. One writer says its "bruised leaves bound on the forehead will relieve most headaches," a natural version of the popular Chinese Tiger Balm, also made with menthol from mint's essential oil. Peppermint is said to repel insects, even mosquitos (I plan to try this soon), and to relieve itching from poison ivy. It has both warming and cooling effects (as does the taste with its initial "hot" whammy and "cool" aftertaste) and can be overstimulating. Herbalists warn against using too much of the oil if you are susceptible to epilepsy. Peppermint, also, is said to inhibit lactation and, like all mints, should be avoided during and after homeopathic treatments since--like coffee and black tea--it interrupts their subtle workings. (Many practitioners say this only happens with dried mint and products made with the essential oils; apparently fresh mint in cooking or salad doesn't jolt the system like this. Perhaps spearmint packs a less-complex wallop: Peter Holmes says it is a "true relaxant;" it does not also stimulate, as does peppermint. Oils of both mints are used in aromatherapy to assist with mental fatigue, headache, colds, coughs, asthma, and bronchitis.

Because they are so green and seem so full of energy, you would expect mints to be nourishing as a food. Apparently they are. Susan Weed lists mint as a good source of eight nutrients. Vitamin B1 (thiamine) for emotional ease and strong nerves and Vitamin B2 (riboflavin) for energy and healthy skin with folic acid for strong, flexible bones and easy nerves. Mint's carotenes also help with bone strength and skin health while also aiding in vision and digestion. The calcium in mint helps us with bone strength as well as sleep and a strong heart and works against depression, mood swings, and headaches, while iron gives us easier nerves and more energy. Phosphorus also helps with energy and bone strength and potassium with energy, blood pressure and digestion. (Weed also recommends a tincture of mint leaves along with chickweed, elder flower, and violet leaf to help cool hot flashes.)

It is worth thinking about how to get mint leaves into your diet beyond the occasional cup of mint tea. My Greek neighbor grows lots in her vegetable garden and says she puts mint in almost every dish. Greek summers are too hot for lettuce and, on my one visit to that country, I fell in love with its delicious salads of sliced mint leaves, onion, and tomatoes dressed with olive oil, salt, and lemon juice. Another favorite from a hot country is an Indian "green chutney" I make by filling my blender with green things roughly chopped--including mint leaves, green onions (especially tops), and one or two jalapenos or other hot green peppers. Add finely chopped ginger and the juice of one lemon, plus just enough water to blend easily. Proportions are not so important as the greenness. After blending, you have a thick green sauce that is extremely satisfying with any Indian dish, including plain rice. And of course, there is everybody's summer favorite: real, old-fashioned iced tea made with both teabags and big bundles of fresh mint stalks and leaves, again with lots of lemon.

Peppermint and spearmint are only the beginning of the mint story. There are also many indigenous mints in temperate and sub-tropical climates. In Mediterranean regions there is Mentha sylvestris, which is thought to be one of the bitter herbs eaten with the Paschal lamb. I am guessing it may be the source of the mythic-tasting "mint tea" given to a friend by nuns in Cyprus last summer or the magical taste another friend keeps seeking to match the mint of his Palestinian childhood. And in New England, there is Mentha arvensis, with its slight, pointy, lightly hairy leaves and flowers in whorls. I once harvested this genuinely wild but minty-tasting mint in Vermont for a good local herb tea. In late August and early September--when mint is coming into flower and has its highest oil content--is the best time to harvest this and many other herbs.

Works consulted include Peter Holmes, The Energetics of Western Herbs, and Susan Weed, Wise Woman Herbal.

Louise Dunlap teaches yoga and writing, and is working on a book called Writing for Social Change.