2-4 feet tall from Long Island to Florida and Louisiana. Plants for sale will include horsemint and many varieties of salvia, which is herb of year for 2001. It's a little picky about growing conditions. Mine grows well now in a partly sunny spot, a dry soil location. I believe it will grow well in sun or part shade, but will not tolerate wet soil.
Dotted horsemint is a source of thymol, which is an anti-bacterial essential oil.
During WWI, thymol wasn't available from the thyme field in Europe, so dotted horsemint was subsidized by the U.S. government as a source of necessary thymol. American Indians also historically prepared a medicinal tea using the leaves of this plant. Historically, it was also used as a liniment in chronic rheumatism, as well as for hearing difficulties, stomach upset, headache, cholera, and typhus.