Bodacious Botanicals: Dotted Horsemint

Having studied biology on some level for more than 40 years, I have seen a wide variety of living organisms.  One of the most striking plants that I have seen is the Dotted Horsemint (Monarda punctata).  It grows to about three feet tall, with clusters of yellow tubular flowers with purple spots on the upper leaf axils.  The bracts (leaves near the flowers) turn white to lilac in color.  The stems are square, a hallmark of the mint family.  The leaves are spearhead shaped (lanceolate) to narrowly oblong and have hairs.  This plant grows in sandy soils from Vermont to southeastern Minnesota and down to Florida and Texas.  Interestingly, the dotted horsemint is missing from the Ohio River drainage.  Horsemint tends to grow in colonies, so if you find one plant, you will likely find others.

Also known as the spotted horsemint or spotted bee balm, the decorative flowers work well in butterfly gardens.  They bloom for a long time, and have showy foliage from July - October.  Pollinators include bumblebees, honeybees, plasterer bees, miner bees, wasps, swallowtail butterflies and the Karner blue butterfly.  Hummingbirds are attracted to the aromatic blossoms, as well.

Dotted horsemint has found many uses by humans through the years.  Being a member of the mint family, it produces several fragrant oils, and the Navajo used them to freshen the air in their hogans.  The plant has been used by several American Indian tribes as a medicine.  It has been used by tribes as diverse as the Meskwaki (Fox), Mohegan, Blackfoot and Nanticoke in teas and powders to relieve stomach cramps, cold, fever and flu.  Poultices on wounds can be used as an antiseptic. 

The plant produces a high content of thymol, which has known medicinal qualities.  Several mints are known to settle a queasy stomach when brewed into a tea.  Thymol can also be used to remove worms from the digestive tract, has antibacterial and antifungal properties.  Thymol has also been used as a miticide and fungicide in beehives.  It shows promise as a way of treating bacteria while reducing the incidence of antimicrobial resistance when used in tandem with antibiotics or antifungals.  Thymol also acts as a depressant through GABA-receptors, which explains some of the calming effects of herbal teas containing mints. 

This nice stand of horsemint was along the nature trail at Illiniwek Village State Historic Site in Clark County, Missouri.  This site contains the only known Illinois Indian village in Missouri.  Although the plant has a wide distribution, the first time I saw it was about 3 years ago on vacation with Nadienne. If you garden with native perennials east of the Rocky Mountains, this would be a showy addition to your collection.