Pollution-free, High-quality and High-efficiency Cultivation Techniques for Chuzhou Chrysanthemum
Chuzhou Chrysanthemum was originally named "Chiju" (pond chrysanthemum), and together with Zhejiang "Hangju" (Hangzhou chrysanthemum), Henan "Huaiju" (Huai chrysanthemum), and Bozhou "Boju" (Bozhou chrysanthemum), it is collectively known as one of China's four famous chrysanthemums. Chuzhou Chrysanthemum is not only enjoyed as an ornamental flower, but is also a precious dual-purpose product for both medicine and tea. During the Guangxu period of the Qing Dynasty, "Chuzhou Chrysanthemum" was once listed as a tribute item, hence it is also called "Gongju" (tribute chrysanthemum) or "Chugongju" (Chuzhou tribute chrysanthemum). It is currently a product under origin protection in China, and the eastern Anhui region is cultivating and developing it on a large scale.
1 Biological Characteristics
1.1 Morphological Characteristics Chuzhou Chrysanthemum belongs to the Asteraceae family and is a perennial root plant, with a plant height of 60-110 cm. The stem is upright and slightly woody at the base, with many branches in the upper part. The stem is green when young and turns purple-brown at the lower old roots after growth. The leaves are alternate, with fine white hairs and prominent veins. The leaves have 4 deep lobes, and each lobe has 4-8 small notches, resembling saw teeth. In autumn, around the "Frost's Descent" solar term, capitula (flower heads) form at the top of the stems, with sword-shaped bracts around them, white petals arranged neatly, about 3-9 layers thick, and yellow tubular flowers in the center. The capitula are used for medicinal and tea purposes.
1.2 Growth Habits Chuzhou Chrysanthemum prefers a warm climate and a sunny environment. It is cold-tolerant, slightly drought-tolerant, and afraid of waterlogging. During the growing period, it requires moist soil, especially near the flowering stage. It grows best in fertile, loose, well-drained soil rich in humus, with a pH value from neutral to slightly acidic.
2 Seedling Propagation
2.1 Division Propagation After picking the flowers in autumn, cut the aboveground stems flat to the ground, then dig them out and replant them in fertile fields, or leave them in place and apply a layer of farmyard manure to keep them warm through the winter. Water and manage them in March to April of the following year. In April to May, when the seedlings grow to 15-20 cm tall, with more than 30% lignification, purple-green stems, a diameter of 0.3-0.5 cm, and 7-9 leaves, dig them all out, select robust plants free of pests and diseases, and divide them into several plants for transplanting. For seedlings propagated through indoor tissue culture and virus-free breeding, they can be transplanted when they reach about 20 cm in height and have more than 10 fibrous roots.
2.2 Cutting Propagation First prepare the seedbed. In April to May, select plump, healthy, disease-free new branches as cuttings. Take the middle sections and cut them into small pieces of 10-15 cm. Cut the lower end diagonally into a horseshoe shape, remove the leaves from the lower 5-7 cm range, dip the roots in 1500-3000 mg/kg indoleacetic acid, or soak the roots of every 10,000 cuttings with 50 g of active root-promoting agent plus 50 g of 50% carbendazim. Dip (soak) and insert as you cut. Insert into the seedbed at a row spacing of 20-25 cm and a plant spacing of 6-7 cm, press firmly and water, keeping the seedbed soil moist. Roots will develop in about 20 days. After 35-45 days, when the seedlings are about 20 cm tall, they can be lifted from the nursery and transplanted.
3 Cultivation Techniques
3.1 Land Selection, Bed Preparation and Transplanting For the field of Chuzhou Chrysanthemum, it is best to choose sandy soil with high and dry terrain, loose texture, deep and fertile soil layers, and good drainage. Plow before planting, apply 1500-2000 kg of decomposed farmyard manure and 20-30 kg of 45% ternary compound fertilizer per mu as base fertilizer, prepare the beds finely, and make beds 130-170 cm wide, 20-25 cm high, with ditch width of 30-40 cm. Prepare drainage ditches around the field.
3.2 Timely Transplanting Choose to transplant in the evening. When planting, pinch off 1-2 cm of the tender shoot tip from the top of the chrysanthemum seedling with your hand to reduce nutrient consumption and promote more branching. Generally, on the prepared bed surface, dig holes at a row spacing and plant spacing of 40 cm x 40 cm and a hole depth of 5-7 cm for planting. Plant 1 plant per hole, cover with soil and press firmly after planting, then immediately water thoroughly to settle the roots.
3.3 Field Management
3.3.1 Cultivation and Weeding Before transplanting, spray with 1000 times dilution of 43% Suancaoling herbicide. After transplanting and survival, especially after rain when the sky clears, promptly hoe weeds, loosen the soil, and earth up around the roots. Before budding, generally carry out cultivation and weeding 3-5 times. The first and second times should be shallow rather than deep, and the third to fifth times should be deep rather than shallow, trying not to damage the roots. In the later period, cultivation should involve hilling soil around the roots to protect the root system and prevent lodging. If conditions permit, 1000 times dilution of 10.8% quizalofop-p-ethyl can be used to control grassy weeds.
3.3.2 Fertilizer and Water Regulation Chuzhou Chrysanthemum is a plant that likes moisture but fears waterlogging. During the growing period, if drought occurs, cultivation and hilling can be combined to improve soil water retention, or dilute manure water can be applied along with fertilizer to supplement water. In addition to applying sufficient base fertilizer, topdressing should be carried out in 3 applications during the growing period. The first application is 15-25 days after transplanting, applying 1000 kg of decomposed human and livestock manure water per mu or 8-10 kg of urea diluted with water. The second application is in mid-August, applying 1500 kg of human and livestock manure water per mu or 20-30 kg of ternary compound fertilizer. The third application is in mid-to-late September, applying 2000 kg of human and livestock manure water per mu or 10-15 kg of urea plus 8-10 kg of ternary compound fertilizer. If conditions permit, spray 0.2% potassium dihydrogen phosphate on the leaves 1-2 times in the late budding stage.
3.3.3 Scientific Topping When the first branch reaches 15-20 cm, promptly pinch off 1-2 cm of the growing tip to control plant height and increase secondary branching. By analogy, generally carry out topping and pinching 2-3 times, finishing before the end of July.
3.3.4 Disease and Pest Control The main diseases and pests of Chuzhou Chrysanthemum include downy mildew, leaf blight, mosaic disease, chrysanthemum longhorn beetle, chrysanthemum aphid, and underground pests such as white grubs. In the early stage of downy mildew and leaf blight, 800-1000 times dilution of 50% carbendazim, or 1000 times dilution of 50% thiram, can be used for control 2-3 times. If mosaic disease is found, promptly remove diseased plants and increase the application of phosphorus and potassium fertilizers. For chrysanthemum longhorn beetle, chrysanthemum aphid, and underground pests such as white grubs, high-efficiency, low-toxicity, safe pesticides such as deltamethrin, imidacloprid, and chlorpyrifos can be used. Stop using pesticides 20 days before flower picking.
4 Harvesting and Drying
4.1 Harvesting The suitable harvesting period for Chuzhou Chrysanthemum is when the tubular flowers (flower center) have opened by 2/3, the petals have unfolded and are jade-white, the stamens are golden yellow, and the true diameter is about 10-15 cm. Generally, harvesting begins in late October, and thereafter once every 7-10 days, for 2-3 harvests. It is best to pick on sunny days after the dew has dried, otherwise the flowers are prone to mold and deterioration.
4.2 Drying First, send the fresh flowers picked on the same day promptly to a processing unit for immediate baking and drying. Second, chrysanthemum growers can themselves spread the harvested fresh flowers on bamboo curtains or straw mats under the open air, sun-dry them until half-dry and the flower color turns white, then place them in a ventilated place to dry in the shade.