What Is the Botanical Family of the Pennyroyal Herb?

The Mint Family

• English Pennyroyal's scientific genus, Mentha, points to its family heritage in the mint or Lamiaceae (Labiatae) family, the original chemical source of menthol. In addition to well-known mints such as peppermint and spearmint, this large plant family includes bee balm, catnip, horehound, hyssop, lavender, lemon balm and self-heal and the aromatic culinary herbs --- from basil, oregano and thyme to rosemary, sage, savory and sweet marjoram. Family members are easily identified. They have very square stems --- you can feel that definite square shape with your fingertips --- and opposite, often hairy leaves. When crushed, both leaves and stems are very aromatic.

The Pennyroyals

• Though English pennyroyal is better known, American or mock pennyroyal (Hedeoma pulegioides) is a low-growing native plant common to dry areas of the eastern U.S. that has very similar chemical properties and is used for many of the same purposes. Mountain pennyroyal (Monardella odoratissima), also known as coyote mint and mountain wild mint, has the same common name but a different chemical makeup. This pungent native plant grows throughout the Sierra Nevada and other areas of the West at higher elevations --- usually in dry, rocky soils --- and is used by backpackers for brewing up mint tea trail side. Native Americans used its crushed leaves as an insect repellent.

Growing Pennyroyal

• English pennyroyal grows naturally in humid, moist, coastal soils surrounding the Mediterranean Sea. For best results grow it like mints and other Mediterranean herbs --- meaning in well-drained, fertile soil with morning sun and afternoon shade --- and keep the ground moist. American pennyroyal is cultivated less frequently, but it does best in dry, sandy soils. To use it fresh or for drying, harvest pennyroyal early in the morning, when volatile oil levels are highest.

Using Pennyroyal

• According to "Herbs: An Indexed Bibliography," pennyroyal has long been used in cooking --- and especially puddings, thus the nickname "pudding weed." Its essential oil is widely used in cosmetics; pulegone extracted from its oil is still the starting point for manufacturing menthol. Pennyroyal has been used medicinally as an antispasmodic, carminative, sedative, stimulant and stomachic. It is pharmaceutically classified as both a diaphoretic --- substance that promotes sweating --- and an emmenagogue --- substance that stimulates blood flow in the pelvis --- so the traditional uses of pennyroyal tea range from relieving cold symptoms and curing headaches to promoting menstruation and inducing abortion. The essential oil can be toxic, and should never be ingested.