- Family: Mint Family – Lamiaceae (Labiatae)
- Growing form: Perennial herb.
- Height: 30–120 cm (12–50 in.). Stem upper part branching, 4-edged, short-haired–almost glabrous, usually partly with purple shades.
- Flower: Corolla irregular (zygomorphic), light red, occasionally white, 8–12 mm (0.32–0.48 in.) long, fused, bilabiate, long-tubed. Upper lip convex, top white-haired, approx. 4 mm long; lower lip 3-lobed, downward-curved, with red spots. Calyx campanulate (bell-shaped), 5-veined, 5-lobed; lobes sharp-pointed. Stamens 4, of which 2 short, 2 long. Gynoecium composed of 2 fused carpels. Inflorescence a spike-like group composed of axillary whorls, terminating stem and branches.
- Leaves: Opposite, stalked. Blade ovate–cordate, usually 5-lobed, margin large-toothed, underside light grey, top sparsely haired. Inflorescence’s subtending bracts usually shallowly 3-lobed.
- Fruit: 4-parted schizocarp. Mericarps 3-edged, brown, upper surface hairy.
- Habitat: Gardens, ruins, roadsides, waste ground, rubbish dumps.
- Flowering time: July–August.
- Endangerment: Near threatened.
Motherwort has also been known as hemp-nettle in Finland on account of the shape of its leaves. The species is foreign in Finland, as it is in almost all of Europe. It is probably native to the eastern and south-eastern corner of Europe, where it began to be cultivated in ancient times. It has been used as a medicinal herb, as can be seen from the fact that it was known as ‘heart-strengthener herb’ in Finland, but it was important that the tea or infusion was administered in the right dosage, because it is poisonous in large quantities. Species were eagerly spread to Finland during the Age of Utility in the 18th century. Motherwort often grows in distinguished old environments because that is where it was cultivated centuries ago. These stands are quite rare in Finland today although even a century a go motherwort was said to be quite abundant in different cultural environments.
In Finland there are two subspecies: ssp. cardiaca, which is dominant in the south-west of the country and the Gulf of Bothnia, and ssp. villosus in the east. Ssp. cardiaca has a short-haired stem, while ssp. villosus is densely covered with spreading hairs, also on its leaves, particularly the underside. Ssp. villosus is probably a later arrival than ssp. cardiaca in Finland.