How to grow Leonurus japonicus for high yield? A detailed guide to cultivation techniques
Leonurus japonicus, also known as Yimucao, Yimu grass, and Shanna, among other names. It is an annual herbaceous plant of the Lamiaceae family. The whole plant is used medicinally, with the effects of promoting blood circulation and regulating menstruation, and promoting diuresis to reduce swelling. Clinically it is mainly used to treat irregular menstruation, dysmenorrhea, amenorrhea, persistent lochia, acute nephritis edema, and other conditions. The seed is known medicinally as Chiongbuzi (fructus Leonuri), with effects of promoting blood circulation and regulating menstruation, and nourishing yin and improving vision. It is mainly used to treat irregular menstruation, postpartum blood stasis pain, and blood-stagnation eye pain, among others.
Morphological characteristics 1. Annual or biennial herb. Stem erect, 60-120 cm tall, obtusely four-angled, slightly grooved, with recurved strigose hairs, much branched. Leaves opposite; petioles slender, 2-3 cm long, the upper ones shorter; lower stem leaves ovate in outline, base broadly cuneate and slightly decurrent, palmately 3-parted, the lobes oblong-rhombic to ovate, usually 2.5-6 cm long and 1.5-4 cm wide, the lobes further divided, adaxially strigose, abaxially sparsely pubescent and glandular-punctate; middle stem leaves rhombic in outline, smaller, usually divided into 3 or occasionally more oblong-linear lobes; bracts nearly sessile, linear or linear-lanceolate, entire or sparsely toothed. Verticillasters axillary, with 8-5 flowers, mostly distant and forming a long spicate inflorescence; bracteoles spiny, shorter than the calyx tube, about 5 mm long; pedicels absent; calyx tubular-campanulate, 6-8 mm long, externally appressed-puberulent, internally pubescent in the upper part, apex with 5 teeth, teeth broadly triangular, apex spinose-acute; corolla pink to pale purplish red, 1-1.2 cm long, corolla tube about 6 mm long, externally pubescent, limb bilabiate, lower lip about equal to upper lip, 3-lobed, middle lobe obcordate, apex slightly emarginate; stamens 4, didynamous, filaments sparsely scaly-hairy; style slightly exceeding the stamens, apex 2-cleft; disc flat-topped. Nutlets oblong-trigonous, 2.5 mm long, light brown, smooth. Flowering June-September, fruiting September-October.
The white-flowered variety of this species, also known as white-flowered Leonurus japonicus, is used medicinally the same as the typical species. The main distinguishing point is that the corolla of this variety is white.
2. Leonurus sibiricus (fine-leaved motherwort) of the Lamiaceae family. The morphological characteristics of this species are very similar to Leonurus japonicus, with the main distinguishing points being: the small lobes into which the leaves are divided are linear, usually 1-3 mm wide, the bracts on the inflorescence are distinctly 3-parted deeply, with the small lobes linear; the corolla is larger, about 1.8 cm long, externally covered with long soft hairs, the lower lip 1/4 shorter than the upper lip; the outside of the calyx, especially in the middle part, is densely sparsely pubescent. Flowering July-September, fruiting September-October. It grows on stony and sandy grasslands and in pine forests, at elevations up to 1500 m.
The white-flowered form of this species' variety is also used medicinally the same, and its difference from the typical species lies in the white corolla.
I. Growth habits: Leonurus japonicus prefers a warm and humid climate. It has relatively strong adaptability. It is not demanding regarding soil, but deep, loose, and fertile sandy loam or loam is best.
II. Land preparation and fertilization: Choose a field with high terrain, good drainage, and deep soil, and cultivate it carefully. In conjunction with land preparation, apply sufficient base fertilizer: 3000 kg of farmyard manure, 10 kg of urea, and 50 kg of phosphate and potassium fertilizer per mu. Then make beds and wait for sowing.
III. Sowing. Leonurus japonicus is propagated by seed, and the sowing period includes spring sowing and summer sowing. Spring sowing is around Qingming, and summer sowing is around Mangzhong. When sowing, use a drill to sow the Leonurus japonicus seeds directly onto the prepared bed surface. Or first open shallow furrows on the prepared bed surface with a drill, then evenly scatter the seeds into the furrows, cover with soil, and water to preserve moisture so as to promote seedling emergence. The sowing rate is 2 kg per mu.
IV. Field management After the Leonurus japonicus seedlings emerge uniformly, attention should be paid to intertillage and weeding. Water promptly in dry weather, and pay attention to drainage in rainy weather. Apply a topdressing once before and after row closure: apply 10 kg of urea and 5 kg of potassium dihydrogen phosphate per mu.
V. Pest and disease control The main diseases of Leonurus japonicus are powdery mildew and rust, which can be controlled with triadimefon at the early stage of onset. Pests include aphids and red spider mites, which can be controlled with pirimicarb and propargite. For underground pests, use phoxim with poisoned bait for trapping and killing.
VI. Harvesting and processing Leonurus japonicus is generally harvested after autumn, when the lower seeds are nearly mature and the upper part is still flowering. When harvesting, cut the plants off at the root, and dry them in the sun before selling them as medicine. The yield is 500 kg per mu.