July 6, 2022
Pennyroyal (Mentha pulegium) is a perennial in the mint family of herbs (Lamiaceae). But don’t let its small size mislead you. As it creeps along the ground, usually only a few inches high, lax prostrate stems root wherever they touch the earth. If you’re searching for something fragrant to fill a semi shaded area of the garden, pennyroyal’s spreading habit will work hard for you.
The name pennyroyal comes from its 1-inch roundish leaves which carry a strong mint flavor. During the summer months, small lavender flowers in tight whorls rise about 4 to 6 inches above the leaves. As with other “mints” pennyroyal prefers cool, moist soil and moderate fertilization.
Although no longer recommended for consumption by humans or animals, pennyroyal has other beneficial properties. Hanging baskets of pennyroyal on the porch will help keep insects away. Fresh leaves rubbed on arms and legs ward off mosquitoes, bees, flies, wasps and even chiggers. Pennyroyal can be used as an aromatic groundcover between stepping stones and in other small spaces.
Choose your location carefully, and allow pennyroyal plenty of room to grow. (Note: My biggest mistake was planting a 4” container of pennyroyal in a 4’ x 8’ x 32” high raised bed. Within months it was creeping along nicely into the bed, putting down roots and taking up my prime herb/vegetable garden space. The only solution was to dig up the entire plant and relocate it to a more confined shady spot with stone borders. It was the right decision.)
Caution: Avoid all contact with pennyroyal if you are pregnant.
Linda Alexander, Dallas County Master Gardener Class of 2008