Cultivation and Primary Processing of Medicinal Chrysanthemums

Huashan GAO, Mengke SONG, Guanhua WANG, Yulin MO, Yuyuan XU, Weishuang TONG

Pingdingshan University, Pingdingshan 467000, China

Abstract The morphological characteristics and growth habits of medicinal chrysanthemums are described, the cultivation techniques are summarized from the aspects of nursery, transplanting and field management, and the harvest and primary processing technology are introduced in detail.

Key words Chrysanthemum, Medicinal use, Characteristics, Cultivation management, Processing technology

1 Introduction

Chrysanthemum (Compositae:Chrysanthemum) is a perennial herbaceous plant, enjoying a reputation of "the delicacy of medicinal food and the best in drinking". Chrysanthemums have a variety of flower types, bright colors, and a long flowering period, and are deeply loved by people. The species resources of chrysanthemum, as one of the four famous flowers in China, are very rich. In general, they can be divided into two categories: ornamental chrysanthemum and medicinal chrysanthemum. Ornamental chrysanthemums are important flowers in landscaping and are widely used in flower beds, potted flowers and cut flowers.

The medicinal use of chrysanthemum was first recorded in the Han Dynasty. In theMateriaMedica, there is a discussion that "long-term consumption of chrysanthemums is beneficial to vitality, lightness, resistance to aging and longevity". As a traditional Chinese medicinal material, medicinal chrysanthemums are mainly used as medicine with capitula. They have a sweet and bitter taste and mild cold nature, and can be used as a daily drink with the functions of dispelling wind, clearing away liver heat, improving eyesight, detoxifying and diminishing inflammation. Medicinal chrysanthemums are very adaptable, and can be cultivated in mountains, plains, and hilly lands throughout the north and south of China, mainly in Anhui, Henan, Zhejiang and Jiangsu. The famous ones include Haoju from Anhui, Hangbaiju from Zhejiang, Huaiju from Henan and Qiju from Hebei, which are known as the "Four Famous Chrysanthemums in China" and are all important Chinese medicinal materials for export. This article describes the morphological characteristics and growth habits of medicinal chrysanthemums, summarizes their cultivation techniques from the aspects of nursery, transplanting and field management, and introduces their harvest and primary processing technology in detail, aiming to promote the cultivation and processing technology of chrysanthemums and lay the foundation for the development of the medicinal chrysanthemum industry.

2 Characters and traits

2.1 Morphological characteristicsChrysanthemum plants are 60-150 cm high. Stems are upright, with many branches. Leaves are alternate, and ovate or lanceolate, with petioles and thick serrated edges. Inflorescences are acrogenous capitula, composed of dozens of small flowers which are densely packed on an oblate torus. Those arranged on the periphery of the inflorescences are ligulate flowers that are white, yellow, light red or slightly purple female flowers. The central part is distributed with tubular flowers, yellow in color, and bisexual.

2.2 Growth habitsThe suitable temperature for the growth of chrysanthemums is 18-21 ℃. They like plenty of sunlight and a warm and humid climate, and are more resistant to cold, but not tolerant to drought. Before the generation of buds, long-day weather with relatively high temperatures is required. Short-day weather is needed from bud generation to flowering stage. Chrysanthemums can tolerate slight frost, and the low temperature resistance limit of underground rhizomes is generally -10 ℃. Therefore, although the above-ground part withers in winter, the perennial roots can survive the winter safely without protective facilities. In the spring of the coming year, new chrysanthemum seedlings can grow from the perennial roots.

Chrysanthemum cultivation requires soil pH between 6.0 and 8.0. Low-lying watery land and heavy saline-alkali land are not suitable for planting. As a shallow-rooted plant, chrysanthemum has a well-developed root system and requires a large amount of water. It should be watered in a timely and appropriate amount. Intertillage should not be too deep. During the last intertillage, the roots of the plants need to be earthed to prevent lodging.

3 Cultivation and management

3.1 NurseryAt present, robust chrysanthemum seedlings are often raised by ramet propagation which not only saves time and effort, and is easy to operate but also make chrysanthemum seedlings cultivated strong in growth, blooming, and high in yield.

After the chrysanthemums are harvested, plants that grow robustly, bloom more, and are free of diseases and insect pests are chosen as the seed stock. The above-ground stems are cut off 3-4 cm from the ground, leaving the roots still. All the litter in the field is removed. In winter, loosened soil and plant ash can be piled up around the base of the chrysanthemum plants, and the thickness of the marl is required to be 10-15 cm higher than the top of the rhizome to protect it from the winter. After the spring of the coming year begins, when the new chrysanthemum seedlings grow out, the roots selected for planting from the previous year are lightly hoed and loosened once and applied with thin human feces and urine or urea solution (100×) one time to promote germination and cultivate robust seedlings. At the same time, at the seedling stage, the prevention and control of leaf spot, downy mildew and aphids should be done well.

3.2 TransplantingFor the cultivation of medicinal chrysanthemums, sunny loam or sandy soil with high terrain, fertile, irritable and drainable soil is preferable. The pH of the soil should between 6.0 and 8.0, and low-lying watery land and heavy saline-alkali land are not suitable for planting.

Before soil preparation, high-quality farmyard manure (60 000 kg/ha), superphosphate (750 kg/ha) and bean cake (600 kg/ha) are applied as base fertilizer. The plowing depth is 30 cm. In order to make the soil flat and the fertilizer and soil fully mixed, after deep ploughing, raking must be carried out in time to ensure that the raking is fine and thorough, the top is loose and the bottom is solid, and the ground is level, thereby facilitating subsequent transplanting.

According to the different climates in the north and south of China, soil preparation is usually carried out from late March to early April. Under this premise, it is necessary to plow in time according to the soil moisture. The soil prepared is required to be flat and fine and have no clod or stubble. After the soil is raked and flattened, ridges, 1.5-2.0 m wide and 25-30 cm high are prepared. In order to facilitate a series of operations such as fertilization and weeding in the later period, ditches (40-50 cm wide) must be dug. At the same time, the ditches can also ensure that the soil can be drained in case of waterlogging and can be irrigated in case of drought, providing a good soil moisture environment for the chrysanthemums.

Around the Grain Rain, in order to avoid water loss that affects the survival rate, the mother plants need to be dug out on a cloudy day or in the evening of a sunny day and divided into individual plants with roots. Robust seedlings with more fibrous roots are retained. The lateral roots and root tips are cut off. The base is retained 20 cm long, and all the upper part is cut off. Thus, each chrysanthemum plant can generate 5-6 new roots after cutting. The prepared chrysanthemum plants are buried into the holes (10 cm deep) that have been dug in the ridges, 1-2 seedlings each hole, at a row and plant spacing of 50 cm×30 cm and watered thoroughly. After the transplanting, the soil around each seedling is compacted.

3.3 Field management

3.3.1Seedling stage. The seedling stage of medicinal chrysanthemums refers to the period from mid-to-late May to early June.

After a certain period of time, the seedlings need to be checked in time. Diseased plants and dead plants need to be dug out in time, replaced by robust seedlings. In order to make the replanted chrysanthemum seedlings survive quickly, an appropriate amount of urea can be mixed with water and poured to the seedlings. After the weather gradually warms up, weeds will grow and they must be removed in time. Chrysanthemum is a shallow-rooted plant. In the very beginning, hoeing should be shallow and just cut through the ground. Then, hoeing is gradually deepened. Earthing should also be carried out to prevent lodging and drought. During intertillage and weeding, care should be taken not to damage the stems of chrysanthemums to reduce the occurrence of pests and diseases. Chrysanthemums like moist soil but they are feared of waterlogging, so water and fertilizer should be controlled during the seedling stage to prevent the seedlings from growing excessively. The soil moisture content that is just enough to ensure the survival of chrysanthemums is preferable. Watering is not needed when the field is not too dry. When necessary, only a small amount of water is irrigated to promote deep rooting and blooming.

3.3.2Branching stage. The branching stage of chrysanthemums is from early June to the end of August.

Chrysanthemums like fertilizer. At the beginning of June, when the plants begin to branch, urea (300 kg/ha) can be sprinkled to the planting ridges in a cloudy or rainy day to promote the growth and branching of chrysanthemum seedlings. If weeds are found in the field during this stage, they should be removed manually. In mid-June, to promote branching, the chrysanthemums can be topped once when the new branches are about 6 cm long. The top buds of the new branches are picked off. After topping, each chrysanthemum plant can produce 11-12 new branches. After late June, especially before the budding, sufficient water is needed. However, if there is too much rainfall, drainage ditches should be dredged to remove the accumulated water in the field in time, to prevent diseases and root rotting. When chrysanthemums grow vigorously from July to August,PhytoeciarufiventrisGautier, grubs and other pests are common. The damaged stem tips must be removed 3-6 cm below the wilting part and burned together. Also, phoxim emulsion (4.5 L/ha) and fine sand (375-450 kg/ha) can be mixed and sprinkled to the ridges in the evening. When using chemical pesticides, it is necessary to strictly control the application amount and safety interval, and eliminate the use of highly toxic and high residue pesticides. The same pesticide can only be applied once in the entire growth cycle of chrysanthemums.

3.3.3Budding stage. The budding stage refers to the period from early September (beginning of budding) to early November (before harvest).

Chrysanthemums have a developed root system and are a fertilizer-loving crop. Re-application of bud fertilizer can promote the growth of chrysanthemums in the later period, achieving more flowering branches, more buds and high yield. Fertilization can be carried out around the Cold Dew, that is, when the chrysanthemums just begin to bud. Borax solution [m(borax)∶m(water) = 750 g∶600-750 kg] can be sprayed on the both sides of the leaves in the morning and evening of a cloudy or sunny day. The amount of spraying on the leaf back should be larger. Afterwards, 0.2% potassium dihydrogen phosphate solution should be sprayed evenly on the leaf surface every 7 d, for 3-4 consecutive times, followed by watering, to promote budding of chrysanthemums. In addition, in case of autumn drought during the budding stage, irrigation should be carried out in time to ensure sufficient water supply. It is strictly forbidden to use chemical pesticides to kill insects after bud formation. It is recommended to promote the use of insecticidal lamps to trap, ensuring the quality of medicinal chrysanthemums.

4 Harvest and processing

4.1 HarvestChrysanthemums bloom unsynchronously, and the petals also spread unsynchronously in the day. Therefore, it is necessary to harvest in batches according to the order of blooming. Too early or late harvest will both affect the yield and quality. Fresh chrysanthemums for processing are generally picked for the first time after the First Frost in early November of the year of planting, accounting for about 50% of the total output. After 5-7 d, second picking is carried out, accounting for 30% of the total output. After another 7 d, usually all the remaining flowers are picked.

The best time for flower picking is when most of the flowers have bloomed, some of the flowers’ edges are purple, the petals are spread, and 60%-70% of flower center has scattered. Flower picking is best done when the dew has dried on a sunny day, so that the flowers picked have low moisture, can be dried quickly, are less prone to decay, and have good color and good quality. But if rainy weather is encountered when the chrysanthemums have been mature, they must also be picked up in time. Otherwise, the water drops wrapped in the petals will not be easy to dry, causing rot and loss. During picking, only the flowers are picked off, without branches or leaves. The flower stalk is first clamped with forefinger and middle finger and then broken. The flowers picked off are placed in a clean and well-ventilated bamboo woven, basket and other containers. If a person is proficient, he/she will pick off 60-75 kg of fresh flowers a day.

After the chrysanthemums are harvested, the above-ground part is cut off, and dead branches and leaves are removed. If the land is dry, it should be watered thoroughly, applied with adequate decomposed organic fertilizer. The chrysanthemum plants should be earthed up to ensure they will overwinter safely.

4.2 ProcessingFresh chrysanthemums cannot be stored. The flowers should be dried immediately after being picked, and must not be stacked, in order to reduce loss. If the processing cannot be completed for a while, the chrysanthemums should be spread thinly in a cool and clean place to dry, with a thickness of 3-6 cm. The thickness should not be too large to prevent the inside fresh chrysanthemums from becoming hot and mildewed and losing processing value. The chrysanthemums should not be air-dried too long, otherwise, the processing quality will be affected.

At present, some medicinal chrysanthemum processing factories adopt the dry processing methods of microwave curing and oven drying. This will not only make chrysanthemums dry quickly, but also have a high drying rate. What’s more, they have the advantage of keeping the shape, color, taste and aroma unchanged.

The chrysanthemum microwave curing machine requires two skilled workers to operate, one responsible for feeding and the other responsible for discharging. When processing, the feeder first places the fresh chrysanthemums on the conveyor belt of the microwave curing machine. In order to ensure the cleanliness of processed products, feeding workers need to wear special gloves. The chrysanthemums should be thinned and evenly spread, treated with two tubes or three tubes for 10-20 s, treated with microwave and sterilized with high temperature. No water is involved in the whole process. Therefore, there is no phenomenon that the chrysanthemums are overwhelmed by boiling water, and thus, the processing quality is guaranteed. After the chrysanthemums are processed by microwave, the steam will quickly condense into water droplets due to the sudden cold, gluing the chrysanthemums together. This requires the worker at the discharge port to hold the bamboo chopsticks and drive the chrysanthemums to separate them, so that the chrysanthemums radiate water and heat evenly.

The dried chrysanthemums are moved to a dryer and dried to constant weight at a temperature of 55-65 ℃. The chrysanthemum automatic dryer needs three skilled workers to operate, two people responsible for the transportation and loading, and the other responsible for the discharge. Using an automatic dryer, the chrysanthemums are automatically fed into the oven by a conveyor belt, 3-4 kg/min. The thickness of the chrysanthemums spread is controlled at 1.0-1.5 cm. They are dried by hot air flow to achieve even heating and thorough heating. Thus, the moisture content is about 10%, less prone to mildewing. Finally, the material is automatically discharged. It should be noted that during the drying process, the degree of drying should be checked at the observation window at any time, and the oven temperature and feeding volume should be adjusted. The degree of drying should be controlled at about 90%, that is, the chrysanthemums do not stick when holding in hands, but they can still be held into a ball, and will disperse after letting go, with great elasticity. If chrysanthemums are sticky when rubbing with hands, it indicates that the water content of the chrysanthemums is relatively high, the temperature of the oven should be increased accordingly, and the amount of feeding should be reduced. If the chrysanthemums do not stick when rubbing with hands, it means that their water content is relatively low, the temperature of the oven should be lower correspondingly, and the feeding amount should be appropriately increased.

After drying, chrysanthemums should be placed in bamboo-woven baskets and other containers to dissipate heat, then air-dried for 3-4 d in a clean, dry and well-ventilated place, and finally packed and put on the market. During the drying process, in order to prevent the chrysanthemums from being exposed to cold and damp, they must be collected indoors every evening and then moved outside for further air-drying next day. In the whole processing process, fresh chrysanthemums are spread out one by one, and the finished product has complete flower shape. Therefore, the chrysanthemums after microwave drying have high quality and are fragrant and dry, without secondary pollution, and they are very popular among consumers. Generally, every 5 kg of fresh chrysanthemums can be processed into 1 kg of dry goods, and thus, per hectare of chrysanthemums can produce 1 500-2 250 kg of dried product.

4.3 Packaging and storageAfter the medicinal chrysanthemums are microwave-cured, mechanically dried, and dried in the sun, they are made into chrysanthemum tea and put into the market. Packaging materials should be dry, clean and free of odors, thereby not affecting product quality. In addition, the packaging must be firm, moisture-proof, tidy, convenient for loading and unloading, storage and transportation, and maintain the quality of dried chrysanthemum products. The packaged products should be stored in a dry, airtight, dark, and cool place to prevent deterioration by moisture and adsorption of peculiar smell.

5 Conclusions

Medicinal chrysanthemums have strong adaptability, high planting efficiency, simple cultivation and processing technology, and strong maneuverability. Their nutrition and health function is getting more and more attention. The processing of chrysanthemum tea is just a primary processing technology of medicinal chrysanthemums. Chrysanthemums as raw material can also be made into chrysanthemum pillows, chrysanthemum wine, chrysanthemum lozenges,etc., with good development prospects and worthy of further promotion.