Reproduction method

Division method

Division is the most commonly used method of propagation for peony. This method is basically used for seedling production in peony producing areas. It has three advantages: first, it blooms earlier than the sowing method. Seedlings bloom in 4 to 5 years, while division seedlings can bloom every other year; second, division is simple and easy to operate, labor-saving to manage, and conducive to wide application; third, it can maintain the excellent traits of the original variety. The disadvantage is that the reproduction coefficient is low. A three-year-old mother plant can only be divided into 3 to 5 daughter plants, which is difficult to adapt to and meet the needs of modern large-scale production and the rapidly growing domestic and foreign flower markets. This has always been a major problem that has plagued the production of peony seedlings.

1. Division time

Theoretically, the division of peony can be carried out from the time when the overwintering buds are full to before the ground freezes. However, if the division is carried out at the right time, the ground temperature is still high, which is conducive to the healing of root wounds, and new roots can be sprouted, enhancing the ability to resist cold and drought, and laying the foundation for the next year's sprouting and growth. Do not divide the plants too early to avoid autumn flowering, which will affect the growth and development of the following year; do not divide the plants too late, because the ground temperature at that time can no longer meet the needs of peony rooting, resulting in poor growth of new plants in the next year; if the division is carried out late in spring, the buds will sprout out of the soil, because the temperature in spring is gradually high, the air temperature is low, and the transpiration is large. After the division, the roots are injured and cannot absorb water and nutrients normally, resulting in the growth of the broken plants being very weak or even dead. Therefore, there is a saying in the agricultural proverb that "if you divide the peony at the spring equinox, it will not bloom until it grows old." The suitable time for peony division is generally earlier than that for tree peony. The agricultural proverb in Heze, "Peony in July, peony in August (referring to the lunar calendar month)", means that in Heze, peony can be divided from the end of August to late September (from the beginning of summer to the autumnal equinox). In Yangzhou, division is done from late September to early November. After three or four years of growth, the division seedlings can be divided again. If they are not divided for a long time, the roots will become old, the plants will grow weak, and the flowering will be poor.

2. Division method

When peony is cultivated for medicinal purposes, peony producing areas mostly use peony heads for division and propagation. In autumn, the mother plant is dug out, and all the thick roots are cut off for medicinal use, while the peony heads with buds are used as propagation materials. First, remove the peony heads without buds and diseased feet, and cut the peony heads into blocks, each with 2 to 3 strong buds. The thickness of the peony heads is 2 cm. If it is too thick, the taproot is not strong and has many forks. If it is too thin, the nutrients are insufficient. It is best to plant as soon as it is divided. If it cannot be planted in time, do not divide it. The peony heads can be stored in sand for later use. It is suitable for planting from early August to late September.

3. Management after division

The planting depth should be about 2 cm when the buds are planted into the soil. Too deep is not conducive to germination and is prone to root rot, yellowing of leaves, and poor growth. Too shallow is not conducive to flowering and is prone to frost damage, and even the rhizome head is exposed to the ground and exposed to the scorching sun in summer, resulting in death. If the root cluster of the ramet is large (with 3 to 5 buds), it may have flowers in the second year, but the shape is small, so it is better to remove them to make the plant grow well. If the root is small (2 to 3 buds), it will grow poorly or not bloom in the second year, and generally needs to be cultivated for 2 to 5 years.

Seeding method

The fruit of peony is a follicle, each containing 1-7 seeds. When the seeds mature, the follicles crack and the seeds are scattered. The fruit maturity period varies from place to place, such as early September in Mudanjiang, Heilongjiang Province, late August in Heze, Shandong, early to mid-August in Luoyang, Henan, and around late August in Yangzhou, Jiangsu. Seeds should be sown immediately after harvesting. As the sowing time is delayed, the water content of the seeds decreases and the germination rate decreases. The seeds have dual dormancy characteristics of the upper and lower hypocotyls. After sowing, the soil temperature in autumn causes the hypocotyl of the seeds to break the dormancy state, and the radicle develops and roots. The better the rooting situation in the current year, the more vigorous the growth in the next year; if the sowing is too late, the ground temperature cannot break the dormancy of the hypocotyl, and it cannot grow well, then the germination rate in the spring of the second year will be greatly reduced. After sowing and rooting in autumn, the dormancy of the upper hypocotyl can be broken after a long period of low temperature in winter. When the temperature rises in the spring of the following year and the humidity is suitable, the embryo will emerge.

Because the offspring produced by sowing peony horticultural varieties will have separate characteristics and cannot maintain the excellent characteristics of the original variety, the sowing method cannot be used for the reproduction of variety seedlings.

When the follicles turn yellow, they can be harvested. If harvested too early, the seeds will not mature. If harvested too late, the seed coat will turn black and hard and it will be difficult for the seedlings to emerge. The fruits mature at different times, so they should be harvested in batches. When the peel cracks and the seeds are released, they can be sown. Do not expose the seeds to the sun, as this will harden the seed coat and affect germination. If sowing is not possible in time, the seeds can be stored in sand for moisture preservation, but they must be taken out and sown before the seeds take root.

2. Sowing time

Peony seeds must be sown in the same year. For example, in Heze, sowing is done from late August to late September. If it is done later than late September, it will not take root in the same year, and the germination rate will be greatly reduced in the spring of the following year. Moreover, even if the seedlings emerge, they are difficult to resist the spring drought due to their underdeveloped root system and are prone to die. Therefore, Heze has failed in several spring sowing experiments.

3. Sowing method

Seed treatment: Before sowing, remove the shriveled seeds and impurities, and then use water selection to remove the unfilled seeds. Although the seed coat of peony seeds is thinner than that of peony seeds and is easier to absorb water and germinate, if the seeds are treated before sowing, the germination will be more uniform and the germination rate will be greatly improved, often reaching more than 80%. The method is to soak the seeds in 50℃ warm water for 24 hours, and then sow them after taking them out.

Preparation and sowing: The land for sowing and seedling raising should be fully fertilized, and the soil should be deep-turned and leveled. If the soil is relatively moist and suitable for sowing, it can be directly sown in the ridges; if the soil moisture is poor, it should be fully irrigated, and then sown in the ridges. The width of the ridge is about 50 cm, the distance between the ridges is 30 cm, and the seeds are sown at a row spacing of 6 cm and a grain spacing of 3 cm; if there are enough seeds, it is feasible to withdraw the seeds, and the grain spacing is not less than 3 cm; after sowing, cover with wet soil with a thickness of about 2 cm. About 50 kg of seeds are used for every 666.7 square meters, and about 100 kg are sown. Cover with mulch after sowing, and remove it after germination and emergence in the spring of the following year. It is also feasible to sow in rows, with a row spacing of 40 cm, a grain spacing of 3 cm, and a covering of 5 to 6 cm of soil; or row and hole sowing, with a hole spacing of 20 to 30 cm, 4 to 5 seeds are placed in each hole, and the soil is piled up 10 to 20 cm after sowing to prevent cold and retain moisture. Harrow it before germination in the spring of the following year.

Other reproduction methods

1. Cutting method: Choose a nursery with high terrain and good drainage as the cutting bed. After the bed soil is loosened, spread 15 cm thick river sand, which should be disinfected with 0.5% potassium permanganate. Vermiculite or perlite can also be used as the cutting medium. Build a 1.5-meter-high sunshade on the bed. According to the experience of Changchun and other places, the best effect of cutting cuttings is to cut cuttings in mid-July. The cuttings are 10 to 15 cm long. With two nodes, the upper compound leaf, leaving a few leaves; the lower compound leaf, including the petiole, is quickly dipped in a 500×10-1000×10 naphthaleneacetic acid or indoleacetic acid solution for cutting treatment. The cutting depth is about 5 cm, and the spacing is based on the leaves not overlapping each other. After inserting, water thoroughly and cover with a plastic shed. It has been observed that the rooting effect is best when the substrate temperature is 28 to 30°C and the humidity is 50%. Keep the temperature in the cutting shed at 20-25℃ and the humidity at 80%-90%. Then the cuttings will take root 20-30 days after cutting and form dormant buds. After taking root, the amount of spraying and watering should be reduced, and the plastic shed and sunshade should be gradually removed. Cutting seedlings grow slowly and need to be covered with soil on the bed to overwinter, and then moved to the open field for planting in the spring of the following year.

2. Root cutting method: Use the roots of peony to cut off when it is divided in autumn, cut into 5-10 cm root segments, insert them into a deep and leveled ditch with a depth of 10-15 cm, cover with 5-10 cm thick fine soil, and water thoroughly.

3. Layering method: In spring, place the newly sprouted buds through the pot holes and introduce them into a pot with a diameter of 15 to 20 cm. Gradually fill the soil as they grow, keep the soil moist, and they will take root in summer. Cut off the stems under the pot before winter to form a potted peony.

4. Modern tissue culture method Plant tissue culture is a plant aseptic culture technology. It is based on the theory that plant cells have omnipotence. It uses the organs, tissues or cells (such as roots, stems, leaves, etc.) of peony in vitro to induce callus, adventitious buds, adventitious roots under sterile and appropriate artificial culture medium and light, temperature and other conditions, and finally forms a complete plant with the same genetic characteristics as the mother plant. This technology is also called cloning technology, which achieves the purpose of rapid reproduction and has the value of wide application.

Field management

1. Land use requirements

The planting site should be a high, dry, well-drained area with a deep, loose and fertile sandy soil. When planting in areas with heavy salinity, the soil needs to be replaced; when planting in low-lying areas, a high platform should be built, and there should be sufficient clean irrigation water. Peony should not be planted continuously. Field cultivation generally rotates once every 3 to 4 years, otherwise the growth will be weakened and pests and diseases will cause serious damage. When it is not possible to rotate on time due to land limitations, deep plowing should be carried out 1-2 months before planting. The depth is 60 to 100 cm. 1500 to 2000 kg of decomposed dry manure or 200 to 250 kg of cake fertilizer can be applied per 666.7 square meters. Remember not to apply undecomposed raw fertilizer.

2. Planting period

Whether it is sowing seedlings or dividing seedlings, the planting time is from late August (End of Heat) to late September (Autumnal Equinox) in Heze, and from late September (Autumnal Equinox) to early November (Beginning of Winter) in Yangzhou. Generally, it is combined with division.

3. Planting specifications

The row spacing for ornamental cultivation in the garden can be 1 meter × 1 meter, and the planting points can be arranged in a "pink shape". This planting can evenly and reasonably use the land and is conducive to the uniform growth of the plants, but field operations are sometimes inconvenient. In order to facilitate field management and observation and recording, a "square shape" arrangement method with horizontal and vertical rows is often used. The specifications of the planting hole are about 35cm deep and 18cm in diameter at the top. The pit should be narrow at the top and wide at the bottom. The thick roots are not removed for ornamental cultivation and propagation. For medicinal cultivation, the root-promoting seedlings after root removal are used (the method in Dongyang, Zhejiang), and the hole is about 25 cm bare. If the rooted peony head is directly used for planting, the depth can be shallower.

4. Planting method

Apply well-rotted dry manure or cake fertilizer to the bottom of the hole. Mix it with the subsoil. Before planting, treat the peony seedlings with a mixture of 700 times thiophanate-methyl and 1000 times methyl isoflavone to prevent pests and diseases. Hold the peony seedlings and place them in the hole with the roots spread out. When the soil is filled to half of the pit, shake and lift the seedlings to make the root system tightly combined with the soil. The height of the seedlings is based on the level of the buds and the ground. After watering, the pit sinks, which is just the appropriate planting depth. If the planting is too deep, the buds are not easy to sprout out of the soil. Even if the seedlings emerge, the growth and development are not vigorous; if the planting is too shallow, the rhizomes are exposed to the ground and are exposed to the sun in summer, which can easily lead to death. Finally, fill the soil until the hole is full, tamp it, and pile up a pile of about 10 cm to prevent cold and retain moisture, which also serves as a sign and protection. Depending on the soil moisture, if the soil is moist, you don’t need to water it after planting. Generally, you should irrigate it after planting.

(1) Digging and leveling the soil: In the autumn of the previous year, the soil piled up during planting must be leveled in time before the peony buds emerge from the soil to make the surface of the ridges smooth, so as to facilitate watering and field management. If the operation is done too late, digging the soil will damage the buds; if the soil is not dug, the base of the buds will be weakened, affecting growth.

(2) Intertillage and weeding: Intertillage and weeding should be carried out frequently throughout the growing season. Deep tillage should be carried out before the leaf curtain completely covers the ground and before and after flowering; shallow tillage should be carried out after flowering. Generally, intertillage and weeding should be carried out about 10 times a year.

(3) Fertilization: Peonies like fertilizer and rarely suffer from excessive fertilizer. Especially when the flower buds are translucent and buds are forming, the demand for fertilizer is more urgent. In addition to applying basal fertilizer during planting, topdressing can be applied three times a year according to the fertilizer requirements of the peony at different development stages. In spring, after the seedlings emerge from the soil and unfold their leaves, "flower fertilizer" can be applied to promote the vigorous growth of the plants and replenish a large amount of fertilizer for the development of flower buds and flowering. In order to replenish fertilizer in time, use more quick-acting fertilizers, and pay attention to appropriately increase the content of phosphorus and potassium fertilizers. After flowering, a large amount of nutrients in the body are consumed, and flower bud differentiation and bud development are required. "Bud fertilizer" can be applied. Whether there is sufficient fertilizer in time at this time is directly related to the quality of flowering and growth in the next year. Quick-acting fertilizer should still be applied. Before winter, combined with wintering, "winter fertilizer" can be applied, mainly long-acting fertilizer, mostly fully decomposed compost, stable manure, or decomposed cake fertilizer and compound fertilizer.

There are three methods of topdressing: hole application, furrow application and general application. For one- or two-year-old seedlings, because the root system is not well developed, the method of inter-plant hole application or inter-row furrow application is often used. The depth of the hole and furrow is about 15 cm. Fertilizer is applied in it and covered with soil. For plants over three years old, the general application method is mostly used. After spreading the fertilizer evenly, it is combined with inter-cultivation and weeding, deep hoeing and loosening the soil to mix it with the soil. For one- or two-year-old seedlings, 150 to 200 kilograms of cake fertilizer or sesame paste residue (the sauce after making sesame paste) or 1,500 kilograms of manure can be applied per 666.7 square meters. For plants over three years old, 200 to 250 kilograms of cake fertilizer or sesame paste residue can be used, or 2,000 to 2,500 kilograms of manure can be used per 666.7 square meters.

(4) Watering: Peonies have a well-developed root system that goes deep into the soil and can absorb water from deep layers of the soil. Their fleshy roots are not tolerant to water and humidity, so they do not need to be watered as often as open-field flowers. However, excessive dryness is also detrimental to their growth, and the flowers are small and sparse, and the color is not bright. It can be seen that moderate moisture is an ecological condition necessary for the normal growth of peonies. Therefore, they still need to be watered in a timely manner even when it is dry, especially before and after flowering and before covering the soil for wintering. Sufficient irrigation must be ensured. When it rains heavily, special attention should be paid to timely drainage to avoid damage to the root system.

(5) Removing side buds: In addition to the main buds on the top of the stem, peony has 3 to 4 side buds in the axils of the upper stem. In order to concentrate nutrients and make the top buds larger, the side buds should be removed shortly after the flower buds appear. To prevent the top buds from being damaged, one side bud can be left first. When the top buds swell and develop normally, the reserved side buds can be removed. Therefore, flower growers have the saying "peony is headed (side buds removed), peony is footed (foot buds removed)". By cleverly using the difference in the flowering period of the main and side buds, the viewing period of peonies can be appropriately extended. You can select some plants of the same variety (varieties with side buds that can bloom normally), remove the main buds, and leave one side bud to bloom, so that the flowering period can be delayed by several days.

(7) Set up a sunshade and rainproof shed: Peony flowering period coincides with the hot and rainy season. During the flowering period, a sunshade and rainproof shed can be set up to block out the strong winds, reduce humidity, and protect against rain, so as to improve the viewing effect and extend the viewing period. The shed is 2.5 meters high and covered with a sunshade net and plastic film. Setting up a shed can extend the flowering period by 8 to 10 days.

(8) Cut off the remaining flowers: After flowering, except for those left for planting, cut off the remaining flowers in time to avoid wasting nutrients.

(9) Cut off the above-ground parts, irrigate with freezing water, and cover with soil for winter: After late October, the above-ground stems and leaves gradually turn yellow and dry. At this time, the dead leaves should be cut off, swept away, and buried deep to prevent the spread of pests and diseases. Then, before the soil freezes in winter, water thoroughly, apply fertilizer, and pile up soil to retain moisture and protect against cold for winter.

Medicinal cultivation

Peony is often cultivated for medicinal purposes, and its root is a traditional Chinese medicine. The root bark is scraped off and is called "white peony". Some wild peony plants, such as Sichuan red peony (P. vitchii) and grass peony (P. obovata), are generally not scraped off when used for medicinal purposes, and are called "red peony". Both are used as medicine but have different medicinal effects.

Medicinal cultivation is similar to ornamental cultivation, but there are also differences. The planting spacing is 50 cm x 40 cm or 50 cm x 35 cm, that is, 3,000 to 3,500 plants are planted per 666.7 square meters. It can be planted in holes or furrows. The seedlings to be planted are ramet seedlings or three-year-old sowing seedlings. If they are ramet seedlings, the new plants should not have too many buds. They can have 1 to 3 buds and 2 roots. If they have 1 bud and 1 root, 2 plants can be planted in each hole. Too many buds will cause the branches and leaves above the ground to grow too long, affecting the growth of the root system. The purpose of medicinal cultivation is to cultivate good roots, so that the roots develop quickly and grow fully. When the plants show buds, remove them all to prevent them from developing and flowering, so that nutrients are concentrated on the growth of the roots. It is best to pick the buds on a sunny day without dew. After picking the buds, spray the equal amount of Bordeaux liquid once to reduce bacterial infection.

After removing the peony root from the peony plant, remove the whiskers, grade it according to thickness, boil and stir, take out the root for observation, and it is suitable when all water marks are air-dried in less than 1 minute (some say that it is suitable when the root epidermis is free of water droplets), take it out immediately and soak it in cold water for about half an hour, scrape off the root skin with a glass piece, a knife, etc., wash it, and dry it. It is best not to expose it in the hot sun to prevent the skin from turning reddish brown. It needs to be dried for about half a month. Thick roots need more time, while thin ones need less time. During the process of drying the roots, dry them for a few days, collect them together and keep them in a draught for one or two days to make them return to moisture, and then dry them again until the roots are broken and pink, and they make a sound when knocked, and then they can be graded and packaged for sale. Usually, they are divided into 3 grades according to the root diameter: first-grade products, with a root diameter of more than 4 cm, second-grade products, 2 to 4 cm, and third-grade products, less than 2 cm. They all require smooth skin, white with pink, and uniform thickness. Generally, 1 kg of fresh roots can get 0.5 kg of dry white peony. After three years of continuous cultivation, about 900 kg of fresh roots were produced per 666.7 square meters, and 450 kg of white peony root was obtained (Heze). In Dongyang, Zhejiang, the white peony root is prepared by removing the root bark first and then boiling it. This method has local characteristics, but the medicinal effect is the same.

Soilless cultivation, also known as hydroponics, is a technology that uses nutrient solution prepared according to the nutrients necessary for plant growth and development to cultivate plants. For the export of potted flowers in the international flower market, soilless cultivation must be used to prevent the spread of pests and diseases. Because it saves water and fertilizer, is clean and hygienic, has fewer pests and diseases, has good product quality, and saves labor in management, it is increasingly widely used.

1. Variety selection

Most peony varieties perform well in nutrient solution cultivation, and are better than general soil cultivation. Varieties suitable for soilless cultivation include "Purple Butterfly Offering Gold", "Oolong Holding Sheng", "Cinnabar Plate", "Yang Fei Out of the Bath", and "Inkstone Pool Waves".

2. Matrix preparation

Peony has fleshy roots, and the substrate requirements are good air permeability, fertilizer retention, and water retention. Vermiculite, perlite, ceramsite, and bark can be used as substrates. Mixed substrates have better effects. The proportions are as follows: vermiculite, perlite, and bark are mixed in a ratio of 1:1:1; vermiculite, perlite, and ceramsite are mixed in a ratio of 1:1:1; or vermiculite and perlite are mixed in a ratio of 1:1. In the south, some local substrates can be added, such as carbonized rice husks.

3. Cultivation form

There are two forms of potted planting and trough planting. For potted planting, the size of the peony plant should be selected according to the size of the flower pot. Clay pots can be used, which have good ventilation and are conducive to plant growth, but they are heavy and inconvenient to manage and use. Plastic pots are commonly used, which have beautiful appearance, light weight, and are easy to use and manage, but have poor ventilation. When planting, a layer of ceramsite is laid on the bottom of the pot to facilitate drainage, and then the peony seedlings are planted, and the mixed matrix is ​​filled in. A layer of ceramsite can be added to the surface to prevent the matrix from splashing out when watering. For trough planting, cement or bricks can be used to build a rectangular cultivation trough with a certain drainage slope on the long axis, about 80 to 120 cm wide, 200 to 300 cm long, and 42 cm deep. Plastic film is laid in the trough, and a 40 cm thick cultivation matrix is ​​filled in. The seedlings are planted with a row spacing of 40 cm × 40 cm, and 2 to 3 rows can be planted. The planting time is the same as the field planting time.

4. Preparation of nutrient solution

Wang Yueying and others from Beijing Forestry University have formulated nutrient solution formulas suitable for three different growth periods by analyzing the nutritional status of peony cultivation soil and determining the nutritional content of peonies in different growth periods: first, it is used from summer to before winter to promote buds and protect roots; second, it is used before flowering, with a high phosphorus content, which promotes beautiful and large flowers; third, it is used after flowering to play a comprehensive fertilization role. This has a high reference value for the preparation of nutrient solution for soilless cultivation of peonies. The mineral element content of the nutrient solution should be between 0.1% and 0.4%.

There are several irrigation methods:

(1) Gravity irrigation facilities: commonly used in general production and cultivation, with simple installation, low investment, convenient management and good use effect. The width of the cultivation trough is 200 cm, and 4 drip irrigation belts can be installed. The size of the nutrient solution storage tank depends on the area of ​​the cultivation trough. Generally, the storage tank can be 150 to 200 cm higher than the surface of the cultivation trough. The gravity generated by the height difference of the liquid is used to deliver the nutrient solution to the roots of the plants through the drip irrigation pipe.

(2) Power irrigation facilities: mostly used for large-scale soilless cultivation. The nutrient solution delivery in the above facilities is changed from gravity delivery to power delivery. An electric pump is added as the delivery power.

(3) Micro-tube sprinkler irrigation facilities: Plastic tubes with many micro-holes are laid on the bed surface to spray the nutrient solution onto the cultivation bed.

(4) Seepage pipe irrigation facilities: Specially made seepage pipes are buried 2 to 10 cm deep in the substrate, allowing the nutrient solution to continuously seep outward. This can save water, ensure uniform irrigation, and is also very convenient to operate.

Promoting and inhibiting cultivation

The cultivation method of using artificial measures to promote the early germination of peony flower buds and blooming earlier than the natural flowering period is called forced cultivation. On the contrary, the cultivation method of using artificial measures to delay the germination of flower buds and bloom later than the natural flowering period is called inhibition cultivation. Both are often called delayed flowering period. On the basis of the natural flowering period in the open field, the flowering period can be reasonably controlled by using the means of forced and inhibited cultivation to make the peony bloom all year round.

The beginning of flower bud differentiation of peony is later than that of tree peony; its early-flowering varieties begin flower bud differentiation at the end of August, while late-flowering varieties start in mid-to-late September. Most varieties form petal primordia from mid-November and stop developing, overwintering in this state. In the spring of the second year, buds will sprout and grow, and flower buds will continue to develop and bloom.

In order to ensure the year-round supply of cut and potted peony flowers, a combination of promoting and inhibiting cultivation is often used to regulate the flowering period. Selecting suitable varieties and strong seedlings with fully developed flower buds and pure varieties; adopting scientific treatment measures and careful cultivation management are the guarantees for the success of promoting and inhibiting cultivation.

1. Forcing cultivation

(1) Variety selection: When cultivating peony, we must first select varieties suitable for forced cultivation. Generally, early-flowering varieties are selected to shorten the time of forced flowering, such as "Qiaoling", "Mozilou", "Yinhe", "Fenronglian", "Dafugui", "Fengyu Luojinchi", "Meiju", etc.

(2) Cold storage: In order to make the peony bloom before the natural flowering period, three or four-year-old strong plants should be selected for cold storage. In the cold storage room, use the soil burying cold storage method, and the buds are slightly exposed. During the cold storage period, check the soil humidity once every half a month. If sandy loam is used, it is best to check the soil humidity just enough to hold it in a ball. Too dry is not good for flowering, and too wet is easy to cause mold and root rot. The humidity in the cold storage room should be maintained at 3°C. Different varieties have different treatment humidity and treatment time. If the plants are refrigerated in early September and then transplanted, at 15°C, they will bloom in 60 to 70 days, that is, they can be put on the market in December; if they need to bloom in January or February of the following year, they can be refrigerated from October to November.

(4) Adjustment of temperature and humidity: After the flowering plants enter the wet room, gradually increase the temperature. The most suitable growth temperature for peony is 20-25℃. Temperatures above 30℃ are not conducive to growth. The following temperature control methods can be used: 15-20℃ in the early stage, about 10 days; 15-25℃ in the middle stage, about 15 days; 20-25℃ in the late stage, about 20-25 days. The high temperature should not exceed 28℃, the low temperature should not be lower than 12℃, and avoid drastic temperature changes. The relative humidity of the air should be maintained at 70%-80%, which can be adjusted by watering, spraying, ventilation, etc.

(5) Supplementary light: Peonies prefer warm and sunny weather. During the winter and spring seasons when they are forced to grow, supplementary light is particularly important. The number of hours of light should be increased to 13 to 15 hours per day to allow the flower buds to fully develop and the flowers to bloom beautifully and large.

(6) Hormone application: Generally, gibberellin (GA3) is used for treatment. When watering after potting, 2000 mg/L GA3 can be used for treatment to further break the dormancy of the buds. When the diameter of the buds is 0.4 cm and 0.8 cm, 600 mg/L GA3 is applied to the buds twice; when the diameter of the buds is 1.2 cm, 1000 mg/L GA3 is applied once.

(7) Other management: When the buds grow to 5-10 cm, remove the buds without buds to avoid wasting nutrients. In the future, pay attention to remove the lateral flower buds, leaving 6-8 flowers per plant. When the flower buds are about to bloom, watering should be controlled for sale or rental. Do not water the flowers after flowering. Place them in a room at 15-20℃, and the flowering period can reach 20-30 days. After the flowers fade, put them back in the room and plant them back in the open field when the temperature is suitable. If used as cut flowers, harvest them as usual and continue to manage them carefully to nourish the roots and promote buds for future use.

2. Suppress cultivation

For suppression cultivation, late-flowering varieties are often used. The following varieties can be considered: "Yang Fei Emerging from the Bath", "Linglong Jade", "Ice Green", "Zhao Garden Powder", "Inkstone Pool Rippling Waves", "Red Goose Flying Box", "Flower Red Tower", "Silver Needle Embroidered Red Robe", etc.

In order to make the peony bloom later than the natural flowering period, two measures can be adopted

(1) Cold storage during dormancy: In early spring, dig up the plants that have not yet sprouted and store them in a cold storage at 0℃ for later use, keeping the plants moist. Depending on the time of use, they can be taken out of the storage 30 to 45 days in advance and cultivated normally, and they will bloom in time.

(2) Refrigeration during the growth period: The buds can be refrigerated when they are about to open. The refrigeration temperature should be higher, at 3-5°C. The refrigeration temperature should be kept until 2-3 days before the flowers are used, and then they can be taken out of the warehouse for conventional cultivation.

The latter method can only be refrigerated in the warehouse for a short period of time, which can be used to extend the normal viewing period. Long-term refrigeration will lead to leggy growth and reduced ornamental value. With the former method, if it is planted in April to August, it will bloom in 30 to 35 days; if it is planted in March or September, it will bloom in about 45 days. When the temperature is too high in midsummer, shading can be carried out, and water spraying can be used to cool down to prevent the high temperature from causing bud shrinkage and leaf burns.

At present, the sales of cut flowers account for about 60% of the total sales in the world flower market. Peony cut flowers have become popular in the world flower market because of their large and colorful flowers, long stems, water resistance, and easy storage and transportation. A certain amount of peony cut flowers are exported every year, and the development prospects are very promising. The following measures should be taken for cut flower cultivation:

1. Select varieties suitable for cut flower applications

The existing varieties are all bred for garden cultivation, and there are no varieties specifically bred for cut flower production. However, some varieties suitable for cut flower applications can still be selected from the existing varieties. Varieties suitable for cut flower production should meet the following conditions:

(1) The flowering rate is high, the flowers are abundant, the pedicels and petioles are stiff, the branches are long, and the leaves are small.

(2) The flowers are neatly shaped, colorful, fragrant, with round buds that are not prone to cracking.

(3) The petals are hard and well-layered, the flower diameter is medium, the flowers open upward, and the buds secrete little sugar.

(4) Cut flowers grow well in water and have a long water-growing period.

(5) The plants grow vigorously, have strong growth potential, strong sprouting ability, strong resistance to stress, few diseases and insect pests, and are resistant to storage and transportation.

When choosing cut flower varieties, attention should be paid to the combination of flower color and flowering period to ensure that they can be supplied to the market throughout the year or for multiple seasons.

2. Field management

Same as above

3. Post-harvest management

(1) Cutting at the right time: When the flower buds are translucent, keep the lower 2 to 3 compound leaves and cut off the flower branches. The best time to cut is between early morning and 10 am. If the cutting task is large, it can also be done in the evening. After cutting the flower branches, put them in a bucket of clean water immediately to prevent water loss.

(2) Grading and packaging: Remove the leaves and grade the flower branches in a low-temperature room. Cut off the two compound leaves on the top and the single leaves near the flower buds. Cut off the remaining compound leaves from the base of the petiole. Wash off the sugar liquid secreted on the flower buds with clean water. The flower branches are divided into five grades according to their length: 50 cm, 55 cm, 60 cm, 65 cm and 70 cm. Wrap each flower bud with soft paper first, and then put it in a corrugated paper tube. According to the variety and the length of the flower branches, 10 branches are tied into a bundle, and then cut at the base according to the length requirements. The base is immersed in 4 mmol/L STS (silver thiosulfate) solution for pretreatment for 10 minutes; then dip it in the fungicide solution at a medium speed, and when it is dried until there are no water droplets on the leaves, the bundled peony cut flowers are packed and shipped out.

(3) Storage and preservation: Based on the research on the post-harvest physiology and preservation technology of cut flowers, in order to extend the life of cut flowers, three major problems must be solved, namely, supplying necessary nutrients, preventing duct blockage, and inhibiting the synthesis of ethylene.

Peony cut flowers cut at the bud stage are treated with STS for 24 hours, then dry-stored in a cold storage at 0-2°C for 3 months. After being taken out and treated with preservative liquid, they still have a water-cultured lifespan and ornamental value similar to that of fresh cut flowers.

Pest and disease control

Peony Diseases

The main diseases of peony are peony gray mold, peony brown spot and peony red spot.

Peony pests

Pest types and damage: There are many types of beetles that harm peony, such as the black velvet gill beetle, apple beetle, yellow hair gill beetle, etc. The adults harm the leaves and flowers of peony; the larvae are grubs, with a nearly cylindrical body that bends into a "C" shape, milky white, with a yellow-brown head, 3 pairs of thoracic legs, and no abdominal legs. They feed on the roots of peony, and the wounds caused create conditions for the infection of Fusarium, leading to the occurrence of root rot.

2. Scale insects

(1) Pests and damage: Scale insects are also known as scale insects. There are several species of scale insects that harm peony, such as the cotton-blowing scale, Japanese wax scale, Changbai shield scale, mulberry white shield scale, peony round scale, arrow-pointed shield scale, etc.

Scale insects suck the body fluids of peony, causing the plant to grow weak and the branches and leaves to turn yellow.

(2) Prevention and control methods

① Strengthen quarantine and strictly prevent the introduction of insect-infested seedlings

②Protect and utilize natural enemies.

③ Spray the insects during the peak hatching period. The surface of the newly hatched insects is not yet covered with wax and is easy to be killed. You can spray 1000-1500 times of 40% omethoate, 800-1000 times of 50% malathion emulsion, or 1000-2000 times of 50% phoxim emulsion. Spray the insects evenly and spray the whole plant. Spraying after the wax shell is formed is ineffective.

④ Use furandan liquid to irrigate the root zone. The plants absorb the medicine and the insects are poisoned after sucking the plant body fluid.

⑤ When you find that individual branches are damaged by scale insects, you can use a soft brush to brush them off, or cut off the infested branches and burn them.

3. Aphids

(1) Damage situation Peonies are often damaged by aphids. When peonies sprout in spring, aphids fly over and suck the sap from the leaves, causing the affected leaves to curl and turn yellow. When the seedlings grow up, aphids often gather on the tender shoots, pedicels, and backs of leaves, causing the stems and leaves of the seedlings to curl and shrink, and even causing the entire plant to wither and die.

(2) Occurrence pattern: Aphids reproduce quickly and cause serious damage under high temperature and dry conditions. Aphids can reproduce several generations or even 20 to 30 generations a year. Aphids secrete nectar, which can hinder the physiological activities of the stems and leaves of the affected plants. At the same time, their nectar is a good culture medium for pathogens, often causing sooty mold disease, etc. Aphids can also spread viral diseases.

(3) Prevention and control methods

①Remove overwintering weeds.

② Protect and utilize natural enemies, the main natural enemies include Harmonia axyridis, Coccinella septempunctata, Coccinella lutea, Tortoiseshell ladybird, aphid fly and lacewings.

③ Spray 1000-1500 times diluted 40% dimethoate emulsion, or 1500-2000 times diluted 80% dichlorvos, or 1000-1500 times diluted 50% aphidicide emulsion.

Cultivation points

"If you plant peonies at the spring equinox, they will not bloom until they grow old" has been proven by many years of practice. The best time for planting and division of peonies is from late September to early October. During this period, you should neither plant them earlier nor later. Peonies are deep-rooted flowers, so you should choose deep pots for planting. For home flower cultivation, you should generally choose deep pots with a diameter of 30cm and a depth of 40cm-50cm. It is appropriate to plant 2-3 plants in each pot. You should pay attention to the cultivation technology. First, spread 3cm-5cm of coal slag as a water filter layer, then fill 15cm-20cm of prepared potting soil, then scatter the seedlings upright in the pot, straighten the root system, and then fill the potting soil. Press lightly while filling the soil to fully combine the root system with the soil. The filling height should be 4cm-5cm higher than the top of the root bud. Water thoroughly to fix the roots, and place it in a ventilated and sunny place for maintenance.

When the root buds emerge in early spring, combine watering and lightly apply a thin liquid fertilizer mainly composed of nitrogen fertilizer to accelerate vegetative growth. In mid-April, the peony enters the bud stage, at which time the vegetative growth is mainly replaced by reproductive growth. It takes about a month from budding to flowering. During this period, you can apply 1-2 times of compound fertilizer (2 catties of fertilizer to 100 catties of water) and spray 2-3 times of 0.2% potassium dihydrogen phosphate fertilizer liquid to promote large and colorful flowers. After the flowering period, cut off the withered flowers in time to reduce nutrient consumption in the body. At the same time, apply a liquid fertilizer mainly composed of nitrogen fertilizer to accelerate the growth of young buds at the roots. In winter, the peony enters a dormant state and the demand for water decreases. As long as the soil remains moist, it will be fine, but it must be combined with inter-cultivation and loosening of the soil and burying an appropriate amount of decomposed cake fertilizer or manure to replenish the nutrients consumed by the soil and lay a good foundation for strong seedlings in spring.