How to Grow Polygala for High Yield? Key Cultivation Techniques Explained

Polygala, also known as xiaocao, shantiaoye, etc. Its root bark is used as medicine, with functions of calming the mind and boosting intelligence, dispersing stagnation and resolving phlegm. It mainly treats palpitations, forgetfulness, cough with excessive phlegm, and other conditions. It mostly grows wild in Northeast China, Northwest China, Shandong, Anhui, and other areas. Due to the reduction of wild resources, it is cultivated on a small scale in various northern provinces. Currently, market supply falls short of demand.

Morphological Characteristics 1. Polygala: A perennial herb of the Polygalaceae family, about 30 m tall, with clustered, slender, hairless stems. Leaves alternate, linear. Racemes one side, flowers greenish-white with purple, 5 sepals, the outer 3 small, the inner 2 petal-like; 3 petals, united at the base, the middle keel petal has a fringed crest-like appendage at the top of its back; 8 stamens, filaments united into a sheath; ovary superior, stigma 2-lobed, unequal in length. Capsule obovate and flattened, slightly concave at the apex, dehiscing along the margin. Seeds ovate, flattened, black, densely covered with white down.

2. Polygala ovatifolia: A perennial herb, 30 cm tall, stems greenish-brown, surface densely covered with grayish-brown fine soft hairs; leaves elliptic to oblong-lanceolate, 0.8-2 cm long, 3-6 mm wide, capsule wings narrow, 1 mm wide or less, sparsely short-ciliate.

I. Growth Habits

Polygala prefers a cool climate, is drought-tolerant, cold-tolerant, and fears waterlogging. It has low soil requirements, but grows well in fertile, deep sandy loam. Heavy clay and low-lying land are not suitable for planting.

II. Land Preparation and Fertilization

Choose a sunny, well-drained plot. Apply 2500 kg of farmyard manure, 50 kg of superphosphate, and 15 kg of potassium fertilizer per mu. Deep plow 25 cm, break up the soil and rake level, and make beds 1.2 m wide.

III. Sowing

Polygala is propagated by seeds. There are two methods: direct sowing and seedling transplanting. Sowing periods include spring sowing, autumn sowing, and summer sowing. Direct sowing: On the prepared bed, sow in rows 20 cm apart, at a depth of 1-2 cm. After sowing, press the soil. In dry conditions, water before sowing. Keep the soil moist after sowing; seedlings emerge in 15 days. Use 2 kg of seed per mu. For dibbling, space plants 10 cm apart. Seedling transplanting: In late March, broadcast sow on the prepared bed surface at a depth of 1 cm. After sowing, cover with grass or plastic film. Keep the seedbed temperature at 15-20°C. Seedlings emerge in about 10 days. After emergence, remove the film or grass. When seedlings are 8-10 cm tall, transplant to the field with row spacing 20 × 10 cm.

IV. Field Management

1. Thinning: When seedlings are 3 cm tall, thin to 3 cm apart; when 8-10 cm tall, final thinning to 5-7 cm apart. 2. Weeding: Polygala plants are short, so weed frequently to prevent weeds from growing taller than the plants and affecting growth. For large-scale planting, apply herbicide for medicinal fields to the soil before seedling emergence to effectively control various weeds. 3. Topdressing: Apply topdressing once in May-June, with 1000 kg of human and livestock manure water per mu, or 100 kg of cake fertilizer, 30 kg of superphosphate, and 10 kg of potassium fertilizer. 4. Irrigation and drainage: Water promptly during drought at the seedling stage. In the rainy season, pay attention to drainage. Water once before winter for overwintering.

V. Pest and Disease Control

Polygala has few diseases. For general diseases, spray 50% mancozeb 800-1000 times dilution for control. For pests such as aphids and red spiders, use conventional control methods. For underground pests, use phoxim mixed with poison bait to trap and kill them.

VI. Harvesting and Processing

After 3-4 years of sowing, harvest Polygala in autumn when the plants turn yellow or in spring before sprouting. While still moist, pull out the woody core and dry in the sun; this is called Polygala root bark. If not cored and dried directly in the sun, it is called Polygala root stick. Generally, the yield is 300-400 kg of dried product per mu.