Around 1790, as French botanist Andre Michaux tromped through the Pennsylvania woods in search of useful plants, he encountered vigorous knee-high masses of a lovely scented plant he called mountain mint. Today, the common name mountain mint is used for more than 20 native species of the genus Pycnanthemum (which means "many clustered flowers"). These include Virginia, thinleaf, Appalachian and Sierra mountain mints, to name just a few.
Many people grow short-toothed mountain mint (P. muticum), also known as clustered mountain mint, for use as an insect repellent. Less hairy than other species and much more pungent, short-toothed mountain mint contains pugelone, the compound that gives pennyroyal its pest-fighting punch. If consumed, pugelone can be toxic to the liver, but it’s perfectly safe to rub a handful of this herb on your pants to deter chiggers and ticks. A fresh wad of short-toothed mountain mint’s bruised stems, stuck into your pocket or hat, might even help keep gnats from buzzing your face when you’re outdoors.
Other mountain mints are valued for their beauty and fragrance, as well as for their ability to attract butterflies and tiny (non-biting) beneficial bees, wasps and flies. Generally, mountain mints with thin leaves and noticeable hairs on their stems contain little or no pugelone, so they are safe to include in teas—or to crush and inhale (think of it as a one-second spa treatment). And, like their close cousins the monardas, mountain mints often develop white or pink pigments in the leaves that frame the flower clusters.
Mountain mints flourish along the edges of woodland areas. If you have a naturalized area or woodland garden in your home landscape, you can encourage mountain mints to grow in any site that receives a half-day of sun. They don’t need rich soil, but try to keep the soil lightly moist through the first half of summer. (Established plants are very tolerant of late-summer drought.) Other plants that share mountain mint’s preference for moist partial shade include elecampane, lady’s mantle, marshmallow, monarda, obedient plant (Physostegia) and sweet cicely.
Deer dislike mountain mint, so consider growing it in areas that often get browsed. Or, plant short-toothed mountain mint near outdoor activity areas so you can swish your hand through the leaves to release a cloud of pest-repellent perfume whenever you visit your garden.
Contributing editor Barbara Pleasant lives in Virginia. She is author of The Whole Herb (Square One, 2004).