Field mint is a herbaceous perennial plant generally growing to and rarely up to tall. It has erect or semi-sprawling squarish stems. The leaves are paired in opposite positions. They are simple, long and broad. Leaves are hairy, and with a coarsely serrated margin. The flowers are pale purple, but rarely white or pink. These are in whorls on the stem at the bases of the leaves. Flower's Length is about . It has a five-lobed hairy calyx, a four-lobed corolla with the uppermost lobe larger than the others. It has four stamens. The fruit is a two-chambered carpel.