Description: Different varieties of this perennial plant exist in both hemispheres. Field Mint is ½–1½' tall, and either erect or having a tendency to sprawl. Generally, the four-angled central stem is hairy or glabrous and little branched. The opposite leaves are 1-2½" long and ½–1" wide, with petioles that are either short or long. The leaves are broadly lanceolate, oblanceolate, or ovate, with conspicuous veins and serrated margins.
Their bottoms may be rounded or wedge-shaped, and their may be pubescent or nearly glabrous. The flowers occur in non-terminal whorls above the axils of the upper leaves. They are tubular, with an upper lip that is divided into 2 lobes and a lower lip. Often, the lower lip is subdivided into 3 lobes, although sometimes the flowers are irregular. Each flower is about 1/8" long, and may be white, pink, or lavender. They usually bloom from early to mid-summer for about a month, but sometimes bloom later. There is no noticeable floral scent, although the foliage exudes a strong mint fragrance that is often detectable before the plant(s) is observed. The green calyx has small triangular lobes and is variably hairy, depending on the variety. The root system readily produces rhizomes, forming sizeable colonies.