Leonurus cardiaca Seeds | Motherwort
LATIN NAME: Leonurus cardiaca
COMMON NAME: Motherwort, Common Motherwort
Plant Profile
Motherwort is a mint in all the structural ways that matter. The stems are square in section and slightly hollow, the leaves sit opposite each other, and the flowers are packed into whorls at the point where each leaf joins the stem.
Each whorl is a verticillaster, a dense ring of small two-lipped flowers that opens from the bottom of the stem upward. The calyx around each flower has five sharp teeth, and those teeth harden and spread as the seed ripens, so the whole calyx becomes a small clinging cup that catches in fur and cloth. The plant has engineered its fruit for transport.
The flower is built for a bee: a hooded upper lip sheltering the stamens, a broad lower lip extending as a landing platform, and a tube too long for a short-tongued insect to rob. The stamens shed their pollen before the stigma of the same flower is receptive, so a bee that works up the spike carries pollen from older flowers to younger ones.
Walk a farm track in late summer and you will often find motherwort growing where nothing was planted: a valued household herb in one century, a listed nuisance in the next.
Motherwort appears in the great English herbals, described by John Gerard and later recommended by Nicholas Culpeper for the heart and the spirits. It was taken as a tea, a conserve or a wine.
Motherwort is listed as a noxious or troublesome weed in several American states, largely because it seeds itself into pasture and waste ground. In a garden it is a dependable nectar plant for bumblebees.
Science & Biotechnology
The aerial parts contain the guanidine alkaloid leonurine, the betaine stachydrine, and a set of iridoid glycosides including leonuride and ajugol, together with bitter diterpenes in the leaf. Stachydrine is the compound most often used as a marker when a batch of the dried herb is assessed.
Leonurine has been studied for its effects on the heart and on smooth muscle, work carried out mostly on the Asian species where the alkaloid occurs in useful amounts. The line of research is real but early, and it sits alongside a much older reputation rather than replacing it.
Because motherwort spreads freely by seed and the seed survives in soil for a long time, it has been both a nuisance in farmland and an easy plant to propagate. Micropropagation from shoot tips has been used to keep selected lines true, which matters when the alkaloid content of wild populations varies as much as it does.
Uses & Benefits
European motherwort and the Chinese drug plant are different species with different chemistry. Leonurus japonicus, sold as leonurus, dominates the herbal trade in East Asia, while L. cardiaca is the plant of European folk practice. Growers and buyers should be clear about which one is on the label, because the two are not used interchangeably in the classical texts.
A simple infusion of the dried aerial parts is the usual domestic preparation; it is thoroughly bitter, so most people take it with honey or in a blend with something sweeter. Two cautions belong with the plant: it has a long traditional association with childbirth, and any herb with that reputation should be avoided in pregnancy, and anyone on heart medication should ask a clinician before using it.
Growing from Seed
Motherwort is not fussy about soil and will grow in anything from gravel to clay, though it does best in a fertile loam with some shade. Sow the seed shallowly, barely covering it, in a prepared tilth and keep the ground damp until the rosettes are up and standing.
Thin the plants to about 40 cm and deadhead the spikes as the flowers fade if you do not want the plant everywhere within a season. Cut the stems back hard after flowering for a second flush of leaf.
Motherwort carries few serious troubles. Powdery mildew can grey the leaves in a close, damp corner and aphids gather on the soft tips in early summer, though opening the clump up usually deals with both. The greater nuisance is the seed, which arrives in beds and lawn for years after the parent plant has gone.
Our Take
Motherwort is the easiest of the heart herbs to grow and the hardest to get rid of, which is a fair bargain for a plant that feeds bees so well. Its Asian relative Leonurus japonicus, is the one to grow if the pharmacy is your interest, while lemon balm and catnip are the gentler mints from the same family for the rest of the border.
Related Reading
Gardeners who grow Motherwort often pair it with these related subjects: