This species is very closely related to Leonurus sibiricus, and was included in that species until 1974. Apart from the differences in habit, this species has a more southerly distribution, extending into the tropics[, ].

Common Name:

General Information

Leonurus japonicus is an erect, annual to short-lived perennial plant growing rom a tuberous rootstock. It produces stems that can be 30 - 120cm tall[, ].
The plant is a popular herbal treatment in Traditional Chinese Medicine and is commonly harvested from the wild and sold in local markets.

Known Hazards

None known

Botanical References

,

Range

E. Asia - China, Japan, Korea, India, Nepal, Bangladesh, Myanmar, Thailand, Cambodia, Laos, Vietnam, Malaysia, Indonesia, Philippines, Australia

Habitat

Waste places, hillsides, roadsides and gardens[]. Sunny areas; at elevations up to 3,400 metres all over China[].

Properties

Weed Potential	Yes
Medicinal Rating
Habit	Annual/Perennial
Height	0.90 m
Pollinators	Bees
Cultivation Status	Wild

Cultivation Details

The plant originates in the temperate zone, but has spread and is now found widely in the subtropics and tropics.
Succeeds in most soils[]. Prefers a poor soil[].
The plant has spread widely from its original range in east Asia and can now be found naturalized in much of the tropics and subtropics[].

Edible Uses

None known

Medicinal

This plant (and other closely related species) is commonly used in Chinese herbalism, where it is considered to be one of the 50 fundamental herbs[]. It is unusual amongst Chinese herbs in that it is often prescribed for use on its own and not in a mixture with other plants[].

The leaves are diuretic and are placed in bath water to relieve itching and painful shingles[].
The aerial parts of the plant are alterative, antibacterial, antifungal, depurative, diuretic, emmenagogue, hypotensive, vasodilator and vulnerary[, ]. The whole plant is decocted, either on its own or with other herbs, as an ophthalmic[]. The plant is commonly used by women to treat a range of menstrual disorders; to hasten the contraction of the uterus and expulsion of the placenta after giving birth; to relieve postpartum abdominal pain; to act as a restorative after child birth; to treat uterine bleeding, leucorrhoea etc[]. It is also used to treat hypertension and heart disease, improve the blood circulation and reduce blood pressure, to treat tumours, oedema, eczema and purulent abscess[, , ].
The plant is used externally as a poultice on bruises[].
Stimulates blood circulation[]. (The part of the plant used is not made clear.)

The juice of the stems is vulnerary[].

The dried flowers are emmenagogue and are also used in pregnancy and to help expel the placenta after giving birth[].

The fruit is antibacterial, diuretic, emmenagogue, hypotensive, ophthalmic and vasodilator[, ]. It is used in the treatment of abnormal menstruation, nebula and conjunctivitis[].

The seed has a sweet, pungent flavour. It is aphrodisiac, diuretic, emmenagogue, ophthalmic and is also used in the treatment of various women's complaints[, , ]. The plant was ranked number one in a survey of 250 potential antifertility plants in China[]. The seed is used in the treatment of conjunctivitis and night blindness[].

The plant is considered a substitute for opium in Java, but its chemical properties are harmless[].

Other Uses

None known

Propagation

Seed - sow spring in a cold frame. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer.