Motherwort is an erect perennial that was introduced to North America and has now naturalized. It grows from 18 inches to five feet on stout, ridged, prominently square, hollow, greenish stems with a few ascending branches.

Leaves are dark green, thin, floppy looking, with a slight rough surface due to fine stiff hair. The larger lower leaves are palmately divided, usually with 5 pointed lobes and from 3 to 4 inches wide. The stalks are as long as the blade causing the drooping look and the stalks are also 4-angled with dense hair on the angles. Middle stem leaves will have 3 lobes and small upper leaves can be lance shaped without lobes. All leaves are prominently veined and have wedge-shaped bases.

The inflorescence is a series of numerous whorl-like clusters containing 6 to 15 flowers, arranged around the stem at the leaf axils of the upper leaves. In the mint family this arrangement is called a 'verticillaster' where the flowers look like a whorl arrangement but are actually in condensed cymes that rise from the axils of a pair of bracts that are opposite each other on the stem.

Flowers: The individual tubular flowers are usually stalkless and composed of a broad upper lip, formed from two fused petals, that is hairy on the upper side and slightly recurved, and then a lower lip, formed from three fused petals, that is split into a center lobe and two side lobes. The side lobes recurve as the flower ages and fold under the center lobe. These corolla parts are usually whitish on the outside and pinkish to purplish on the inside and short - 1/3 to 1/2 inch long. There are 4 stamens, paired, the 2 in front being the longest, and one style. The outer calyx tube is green with 5 sharp pointed teeth. Imp: In this species each flower is shorter in length then the leaf stalk it is next to.

Fruit: Flowers mature to a brown capsule with 4 brown nutlets that are 3-angled, 2 to 3 mm long, and with fine bristly hair on their apex.

Habitat: Motherwort grows best in partial sun with moist rich soil. It will show up along woodland edges and disturbed areas. It grows from a rhizomatous root system which will from colonies by the spreading of the rhizomes. It is not considered invasive by any state.

Names: The genus name Leonurus, is from the Greek meaning 'lion's tail' which some species of this genus were thought to resemble. The species name, cardiaca, refers to 'the heart' and references the old medicinal use of the plant as explained below. The common name of Motherwort is also explained below by Culpepper. The author name for the plant classification, 'L.', refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.

Comparisons: Members of the mint family tend to have flowers in what look like whorls around the stem at the leaf axils. Motherwort's lobed leaves are distinctive. Compare Wild Mint, Mentha arvensis.