High-yield greenhouse cultivation techniques for rose cuttings

Growing Techniques Jan 1, 1970 0 views

Roses are grown in many parts of China. Places such as Yongdeng in Gansu, where the natural conditions and environmental characteristics suit rose cultivation and production, have a long history and enjoy a high reputation

I. Morphological characteristics and growth habits

1.1 Morphological characteristics

An upright shrub, 100-200 cm tall, with 5-7 leaflets that are round or oval; the petals curl backward, and the flowers come in a rich range of colors. The stems are thick and grow in clusters, densely covered with prickles, usually solitary, clustered or terminal, but mostly clustered.

1.2 Growth habits

Roses like a growing environment with plenty of sunlight and are relatively drought-tolerant and cold-tolerant. They prefer well-drained, deep, fertile and loose soil.

Roses are heliophilous plants and need abundant sunshine during the growing season, generally no less than 8 h per day. They also have requirements for air temperature and humidity. Insufficient temperature and excessive moisture easily trigger rust and powdery mildew, while overly dry conditions or too high a temperature affect growth and development and reduce yield. The most suitable temperature for rose growth is 15-26 degC, and the most suitable air humidity is 75%-80%. When the greenhouse temperature exceeds 30 degC, growth is inhibited, flower buds no longer differentiate, and prolonged high temperatures can kill the seedlings; when the greenhouse temperature falls below 15 degC, the plants enter dormancy and stop growing. Therefore, attention must be paid to heat preservation measures for roses to avoid damage that affects growth. The requirements for soil are relatively less strict, and they can grow under slightly acidic or slightly alkaline conditions.

II. Cultivation techniques

2.1 Land leveling, greenhouse selection and fertilization

2.1.1 Land leveling. For greenhouse planting, choose a plot that is open and level, has sufficient light, and offers convenient irrigation, ventilation and drainage.

2.1.2 Greenhouse selection and fertilization. Use an ordinary solar greenhouse of northern type, covered with drip-free plastic film; considering ventilation and other factors, the solar greenhouse needs ventilation facilities. Before planting roses, plow and level the land in advance to ensure the soil is loose and suitable. In combination with land preparation, apply decomposed cow manure, peat and an appropriate amount of chemical fertilizer as base fertilizer to ensure sufficient nutrients in the greenhouse.

2.2 Planting

2.2.1 Preparatory work before planting. Before planting, the entire plot needs to be irrigated once, a process lasting half a month, in order to soak the land thoroughly so that the soil inside becomes moist and settles firmly. At the same time, spray pesticides to prevent and control pests and diseases.

2.2.2 Planting. Keep the soil moist when planting, and use rose seedlings with many roots and strong, fresh branches and leaves. When planting, bury 2/3 of the seedling in the soil and leave 1/3 above the ground; note that too much force must not be used, and the seedling should only be planted gently into the soil to avoid damaging it. The planting density of rose seedlings is 20 cm between plants and 30-40 cm between rows. After planting, fill soil around them and press it firm, and water thoroughly at the base.

2.3 Fertilization and irrigation management

2.3.1 Fertilization and irrigation methods. In greenhouse cultivation, drip irrigation is generally used. When installing drip irrigation facilities, every aisle needs a water pipe connected to drip lines, which can improve the utilization rate of water and fertilizer. The principle of topdressing is to mainly use organic fertilizer, combine it with phosphorus and potassium, and apply small amounts frequently, focusing mainly on early spring sprouting, the bud stage and the flowering stage.

2.3.2 Irrigation timing. After planting, water promptly, usually once every 10 days, so that the roots fully contact the soil and absorb nutrients and water more effectively. Spray with clean water every morning to maintain humidity inside the greenhouse.

2.4 Intertillage and weeding

During the rose growing period, weeding is also a very important step. To prevent weeds from growing and pests and diseases from causing damage, while also protecting flower growth, chemical pesticides cannot be used directly and weeds need to be pulled by hand. At the same time, in combination with weeding, manual intertillage and loosening of the soil between rose rows are needed to increase soil aeration, encourage root extension, and provide better conditions for rose growth.

2.6 Pruning and renewal

During the vigorous growth period, rose branches and leaves are often lush and interwoven, so branches and leaves must be pruned in time to ensure ventilation and light penetration and prevent pests and diseases. When pruning, combine it with the specific situation and prune scientifically; do not cut off too much and affect yield, nor leave branches too dense and cause pests and diseases. Generally, no pruning is needed in the first 3 years, and from the 4th year the plants begin to age and require appropriate pruning and renewal.

Rose pruning is divided into renewal pruning and thinning pruning. Renewal pruning is mostly a kind of renewal and maintenance done so that the plants grow vigorously and can produce better and more flowers, while thinning pruning mainly refers to cutting work done on the root area of roses, mainly removing residual branches, dead branches, old branches and diseased branches.

III. Harvesting and storage

Because the flowering period of roses is relatively short, they need to be harvested quickly. The most suitable picking period is from early morning until dark. After flowers are picked, the storage time should preferably not exceed 2 h so that the freshness of the flowers can be maintained. After harvesting the flowers, dig trenches around the plants and fill them with decomposed organic farm manure, and at the same time cut off dead branches, diseased branches and crossing branches.

Rose planting methods and cultivation techniques

Roses belong to the order Rosales and the family Rosaceae. They are deciduous shrubs with many prickles on the branches, odd-pinnate compound leaves, 5-9 leaflets, oval in shape, densely covered with white down on the underside and with marginal prickles. The petals are obovate, double to semi-double, and the flowers are purplish red or white. The fruiting period is August-September, and the fruit is oblate.

Soil preparation

Roses are perennial woody plants with a long production cycle. Cuttings planted once can be harvested for 3-4 years, and grafted seedlings can be harvested for 5-6 years. To obtain high-quality, high-yield and high-benefit cut flowers, the soil for planting roses must have good physical and chemical properties during cultivation. It is best to choose a loamy clay soil with a low groundwater table that is loose and airy. The soil needs to be rich in organic matter, preferably with a content of more than 10%. The soil pH value is around 6.5. Soil improvement should be carried out in combination with preparing the planting beds, by deep plowing and applying large amounts of organic fertilizer, so that the permeability and water- and fertilizer-holding capacity of the soil are improved and maintained over the long term, promoting long-term good growth of the rose root system. Organic fertilizers for improving the soil can include cow manure, pig manure, sheep manure, chicken manure, bone meal, leaf mold, compost, etc.

The planting beds are made with a bed surface width of 0.9 m, an aisle bottom width of 0.5 m, and a bed height of 0.5 m, and the bed surface should be level. After the planting beds are prepared, check the soil pH value and EC value again, and adjust them with fertilizer, acid or alkali so that the pH value is adjusted to about 6.5 and the EC value to 0.8-1.2 mS/cm. If the EC value is less than 0.8, adjust it with fertilizer; if the EC value is greater than 1.2, it can be leached with water. Install drip irrigation in advance.

Cultivation method and planting

Rose production mostly adopts the bent-branch cultivation method, with a single-bed, double-row cultivation pattern, 12 cm between plants and 50 cm between rows, planting 5,000-6,000 plants per mu. Greenhouse cultivation can be planted all year round. When planting, plant along a drawn line to ensure the seedlings in the planting row are straight, which is helpful for management. The planting depth should be slightly deeper than the cutting depth, but the soil must not cover the main bud of the seedling. Seedlings from modern factory production have a short rejuvenation period and establish quickly.

After planting, water thoroughly in time to settle the roots. When planting in hot weather, pay attention to shading and cooling and spray water on the leaves. Within one week after planting, fully ensure that the root soil and surface soil are moist, spray water on the leaves during the day, and provide appropriate shading; after 7 days, gradually reduce the amount of leaf spraying, but keep the surface soil moist, and spray fungicides such as carbendazim or chlorothalonil once to prevent and control diseases; after 15 days, gradually reduce the amount of soil watering, and thereafter water appropriately according to whether the soil is dry or wet to keep the soil moist, and begin using the drip irrigation system; after 30 days, enter normal management.

Cultivation environment control

The rose cultivation environment mainly includes environmental factors such as water, fertilization, temperature, humidity and light.

1. Water management

For irrigation water, choose unpolluted river water, spring water or well water. The watering time, watering frequency and watering amount for roses are affected by season, weather, soil and plant growth conditions, and producers mainly determine them based on production experience or instruments by continuously observing and testing soil moisture content, plant growth conditions, etc. A soil tensiometer for rapid determination of soil moisture can be used as the instrument. Use the tensiometer to monitor soil moisture and create a reference basis for drip irrigation watering. On sunny days, water 2 times per day (keep the soil moisture tension PF at around 1.8), choosing watering times of 10:00 and 14:00. Do not water in the morning or evening, to avoid lowering the soil temperature because of low water temperature. From April to June, the temperature is high and dry, the cultivation soil is also relatively dry, and rose plants grow faster, so water consumption also increases. Mainly increase the number of waterings to increase soil moisture; keep the soil moisture tension PF at 1.6-1.8, and choose to water on sunny days from 10:00 to 16:00. Greenhouses without cooling facilities need to increase mist cooling, choosing the misting time at 14:00 on sunny days. From July to September, the temperature is high, there is more rain, humidity is high, and the cultivation soil is relatively moist, but rose plants also grow very fast and need to consume large amounts of water. By increasing the amount of water each time, meet the large water demand of rose plant growth, and keep the soil moisture tension PF at 2.2; on cloudy days, to reduce air humidity and decrease the occurrence of pests and diseases, water only once at 10:00. On continuous rainy days, stop watering, and after the rain stops and the weather clears, water promptly, which is beneficial for regulating and controlling the air humidity in the greenhouse. In autumn, the weather is cool and relatively suitable for the growth of rose cut flowers. Keep watering 1-2 times per day, and keep the soil moisture tension PF at around 1.8.

2. Fertilization management

During the vegetative growth period, the demand of roses for the major elements nitrogen, phosphorus and potassium is 3:1:2, and during the flowering period it is 3:1:3. Secondary elements and trace elements can be applied regularly every month. Secondary elements include calcium, magnesium and sulfur; river water and well water contain relatively high calcium and magnesium, so they may not be added or may be added in smaller amounts during fertilization. Among trace elements, zinc and boron are relatively deficient, and attention should be paid to adding them in production. Iron is not deficient in the soil, but iron absorption is related to soil pH. When the pH value is 5.5-6.5, a small amount can be added; when the pH is greater than 7, it is very difficult for plants to absorb iron in the soil. In production, soil nutrients should be tested regularly, and according to the test results, judge whether the various nutrient elements in the soil can meet the normal growth and development of roses. When the various nutrient elements in the soil reach the optimum values, relatively good cut flower yield and quality can be obtained. Refer to the table below for the optimum values. If a nutrient element in the soil is insufficient or relatively low, it can be gradually increased each time by 10% of the original fertilization amount until the optimum amount is reached; if a nutrient element in the soil is too high, reduce the fertilization amount or leach with water. Roses have a well-developed root system, grow quickly and have high flower yield, so their demand for soil nutrients is quite large, and their nutrient requirements are diverse. Only when different types of nutrients are reasonably combined can fresh flowers be high-quality and high-yield and achieve bumper harvests year after year.

(1) Different effects of different types of nutrients on roses

Nitrogen fertilizer is an important nutrient required by roses and plays an important role in the vegetative growth of roses and fresh flower yield. Only when nitrogen fertilizer is supplied sufficiently can the plants have luxuriant branches and leaves and grow normally. If nitrogen fertilizer is insufficient, rose branches become thin and weak, leaves turn yellow, and new shoots grow slowly. However, if there is too much nitrogen fertilizer in the soil, it easily causes excessive vegetative growth of branches, loose tissues, fewer flowers, and even deformed flowers.

Phosphorus fertilizer can promote rose root growth, making the root system well developed, the leaves thick, and the flower colors bright. If the soil lacks phosphorus fertilizer, the branches become weak and the flowers droop weakly, so when applying base fertilizer in autumn each year, an appropriate amount of phosphorus fertilizer should be mixed in.

Potassium fertilizer can promote normal growth of new rose shoots and young leaves, increase the number of fresh flowers, make flower buds plump, and increase the rose oil content of the fresh flowers.

In addition to the three major nutrient elements nitrogen, phosphorus and potassium, which are needed in large amounts, roses also need certain trace elements, such as iron, boron, manganese, zinc, etc. If the soil lacks trace elements, plant leaves become chlorotic, and even plant organs become deformed, various physiological diseases occur, and the normal growth and development of rose plants are affected.

(2) Types of commonly used chemical fertilizers for roses and fertilization requirements

a. Urea. Urea is a nitrogen fertilizer often used in rose production and is mainly used as topdressing. Topdressing generally adopts trench application and hole application, and takes effect 5-7 days after fertilization. After applying urea, water promptly. The usual amount per mu each time is generally 10-15 kg. Urea can be applied as topdressing 3-4 times per year. For sandy soil, attention should be paid to frequent and small applications.

b. Ammonium bicarbonate. Abbreviated as ammonium bicarbonate, it is a quick-acting nitrogen fertilizer and can only be used as topdressing, by trench application or hole application. Broadcasting on the surface is taboo because it volatilizes quickly; cover with soil promptly and combine with watering. It takes effect within 2 days after fertilization. When fertilizing, do not let the fertilizer fall on plant leaves and burn them. The amount per mu each time is 10-20 kg, and it can be applied as topdressing 3-4 times per year. This fertilizer dissolves easily and is lost, so special attention should be paid to frequent and small applications. Long-term use of this fertilizer will not damage soil structure or cause soil compaction, so it is widely used in production.

c. Superphosphate. It is mainly used as base fertilizer and has a slow fertilizer effect. In production it is often mixed with soil and miscellaneous manure and used as base fertilizer in autumn. Trench application is the main method, and the usual amount per mu is generally 30-50 kg. Superphosphate easily cakes, so it should be fully crushed or pounded when used, otherwise it will burn plant roots. In late autumn growth of roses, a 1% superphosphate extract can be used for foliar fertilization, and the effect is also very good.

d. Calcium magnesium phosphate. The properties, usage and dosage of calcium magnesium phosphate fertilizer are the same as those of superphosphate, but calcium magnesium phosphate fertilizer is non-corrosive, does not absorb moisture, does not cake, and is convenient to use, so it is widely adopted in production.

e. Potassium sulfate. Potassium sulfate has low mobility in soil, so it can be used as base fertilizer or topdressing, and topdressing before rose budding is especially best, with remarkable effects. The higher the yield of a rose garden, the more potassium fertilizer topdressing is needed. Potassium sulfate is generally applied in trenches, with a usual amount of 10-15 kg per mu, and topdressing once per year is sufficient. Long-term use of potassium sulfate can cause soil compaction, so it is better to mix it into organic fertilizer as base fertilizer. Potassium sulfate is acidic and somewhat corrosive, so contact with branches and leaves should be avoided to prevent burning. Potassium sulfate must not be mixed with nitrogen fertilizer or superphosphate, otherwise the fertilizer efficiency will be seriously reduced. For roses, foliar fertilization with potassium sulfate before budding has a very good effect; the concentration used is 0.5%, absorption is fast, and the effect is obvious.

f. Potassium chloride. The properties, usage and dosage of potassium chloride are basically the same as those of potassium sulfate. Potassium chloride should not be used on saline-alkali land.

g. Diammonium phosphate. Diammonium phosphate is a very good nitrogen-phosphorus compound fertilizer with a long fertilizer effect and high fertilizer efficiency. It is mainly suitable as base fertilizer, mainly by trench application, with a usual amount of 30-50 kg per mu. When diammonium phosphate has already been added to the base fertilizer, phosphorus fertilizer does not need to be added again.

h. Potassium dihydrogen phosphate. Potassium dihydrogen phosphate is a phosphorus-potassium composite material with high solubility and is suitable as a foliar fertilizer. The conventional concentration used is 0.2%-0.3%, generally sprayed once every 15 days. It can also be applied together with pesticide spraying.

(3) Fertilization timing

The types of rose fertilization include base fertilizer and topdressing.

a. Base fertilizer. Rose base fertilizer is applied after leaf fall in autumn, and the fertilization time should be as early as possible. Applying base fertilizer early in autumn can not only heal the roots injured during trench fertilization and produce new roots, but also allow the applied soil and miscellaneous manure to fully decompose and break down in the soil, which is beneficial for promoting vigorous plant growth the following spring. The specific time in northern regions should preferably be from late September to early October. If autumn base fertilizer is applied too late, it often affects normal plant growth the following spring.

b. Topdressing. Rose topdressing is carried out during the spring and summer growing seasons. The fertilizers applied are mainly chemical fertilizers, with quick fertilizer effects and strong targeting. The specific topdressing time can be divided into 4 periods: the sprouting stage, the flower bud stage, the full flowering stage and the post-flowering stage. In these 4 periods, plant growth is large and fertilizer demand is high, so nutrients should be replenished into the soil in time to ensure fresh flower yield. The fertilization experience of flower growers in rose-producing areas of southern China is: "three-five flowers red" and "four waterings and three fertilizations to finish harvesting the flowers." This means that from the beginning of flower bud formation in roses to the complete completion of fresh flower harvesting, 4 waterings and 3 fertilizations are required. This is enough to show that applying chemical fertilizer multiple times during the rose flowering period is of extremely important significance for fresh flower yield.

3. Temperature control

The most suitable growth and development temperatures for rose production are 24 degC-26 degC during the day and 14 degC-16 degC at night. In winter, when the night temperature is lower than 8 degC, growth is slow, branches become shorter, and double-centered flowers increase. When the night temperature is below 5 degC for a long time, the new branches produced are shorter and blind branches increase. The ideal day-night temperature difference is 10 degC-12 degC.

Install temperature and humidity recorders or dry-and-wet thermometers in the greenhouse to observe temperature changes inside and carry out temperature regulation management according to the changes. When the temperature is on the high side, open the skylight and side windows around the greenhouse for natural ventilation and cooling. When the daytime temperature is higher than 30 degC, use shading to cool down. In hot and dry seasons, mist cooling can be used; when the temperature is on the low side, close the side windows around the greenhouse, and add a thermal screen inside the greenhouse for insulation. At night, the thermal screen is mainly used to prevent heat exchange and loss, raise the temperature of plant leaves and prevent dew formation, thereby increasing yield and improving cut flower quality, especially for red varieties, but the thermal screen cannot always be fully closed during the day.

4. Humidity control

The relative humidity required during the rose sprouting and branch and leaf growth period is 70%-80%, and the relative humidity required during the flowering period is 40%-60%. During the day, humidity should be controlled at 40%, and at night it should preferably be controlled at 60%. When the humidity in the greenhouse is above 90%, water droplets begin to form on the greenhouse film, gutters, plants and leaves, easily inducing many diseases. Soil moisture conditions are crucial to rose growth, development and yield, and changes in soil moisture conditions must be closely monitored throughout the rose growing season. Generally speaking, spring in northern China is relatively dry, so sprouting water, flower-promoting water, full-flowering water and post-flowering water should be applied in time, about once every 15-20 days, to always maintain good soil moisture. In actual production, watering and fertilization are carried out in combination. After each topdressing, as long as it does not rain immediately, water once promptly, otherwise the topdressing will not achieve the ideal effect. Rose garden watering generally adopts border irrigation, but this method uses a large amount of water and easily causes a large loss of soil nutrients, so the water amount should be controlled when watering, with the appropriate amount being enough to soak the root-zone soil. In production, narrow-border irrigation should be advocated, which can save a large amount of water. Where conditions permit, rose gardens should develop drip irrigation, which can not only save a large amount of water, but also always maintain soil aeration and prevent soil compaction.

5. Light control

Roses like light, especially scattered light. The light saturation point of the leaves is 35,000-50,000 Lux, and the light compensation point is 10,000 Lux. The synthesis of anthocyanins in cut roses requires ultraviolet light, but too strong ultraviolet light can cause black edges on the petals of red varieties. For red varieties, it is suitable to choose greenhouse film with a transmittance of about 20% in the 0-350 nm band. On cloudy and rainy days, a certain amount of scattered light must be ensured. Do not use shade nets during the rose branch-shooting period, so as to ensure the plants have sufficient light; after budding, a 60%-75% silver-gray shade net can be used from 10:00 to 16:00 on sunny days; on continuous cloudy and rainy days in summer, do not shade, and do not shade in winter. When the greenhouse soil surface is too wet, or there is downy mildew or gray mold, do not shade.

6. Intertillage and weeding

After each watering and rainfall, the rose garden should be intertilled and weeded in time, which can not only loosen the soil but also prevent weed growth and stop weeds from competing with roses for water and nutrients. Every year when the rainy season arrives, the rose garden should be intertilled multiple times so as to effectively loosen the surface soil, increase soil permeability, improve soil air conditions, ensure normal root growth, and prevent diseases such as root rot.

Rose pruning techniques

1. Plant shape training

At the seedling stage, all flower heads are removed when they are the size of a pea, and the leaves are retained. When branches are more than 50 cm long, bend the branches down, taking care not to break them. Newly sprouted thick branches are used as cut flower branches, and overly thin branches are bent down as vegetative branches; thin and weak branches growing from vegetative branches continue to be bent down. When bending branches, note that plants and branches must not cross each other. The number of bent branches should preferably be enough to cover the side of the bed, so that the leaves can receive sufficient light. Bending should generally be done on a sunny afternoon. While pruning vegetative branches, remove thin and weak branches and short branches within 10 cm of the root area, which can increase light in the lower part and promote sprouting.

2. Pruning during the flowering period

The pruning principle is to leave low stubs in spring and summer and high stubs in autumn and winter. For branches with a lower-part diameter of about 0.5 cm, retain 2-3 buds; for branches with a lower-part diameter of about 0.8 cm, retain 3-5 buds; promptly cut off branches less than 50 cm long or blind flowers, deformed flowers, and branches with a diameter above 0.5 cm; for branches with a diameter below 0.5 cm and a relatively high sprouting position, prune them, either by cutting close to the stub or by retractive pruning of the main branch, while branches with low sprouting positions are directly bent down as vegetative branches. The general principle is: thick branches are raised upward, thin branches are bent downward.

3. Rose training

Training means cutting all rose branches from the base, while pruning means cutting off only a small part of the branches. To promote vigorous growth of rose bushes, bright flower color and high oil yield, appropriate training and pruning must be carried out. Rugosa roses are upright and clustered, with strong sprouting ability. When pruning, attention should be paid to ventilation and light penetration, and the branches should be evenly distributed and kept at a certain distance to prevent the wind from blowing branches against each other and damaging the flower heads. After the bushes are pruned, flower harvesting and field management operations can be made more convenient. For newly planted one- to two-year-old rose bushes, after pruning they should not only grow well in branches and leaves, but also be able to bloom earlier. Rose gardens more than three years old have very high fresh flower yields and need timely pruning to prevent premature aging from causing yield reduction. To prune roses well, one must understand the response after pruning. Because rose varieties differ, cultivation and management levels differ, and soil and fertilizer differ, the responses after pruning also differ. Through pruning, rose branches should become thick and strong, and the buds on the upper half are better in quality than those at the base, sprout earlier and grow vigorously. Pruning and training must take into account the varietal characteristics and growth habits of roses and master the pruning principles. When pruning, vigorous branches should be controlled from growing excessively upward, and the shoot tips should be cut at an appropriate position to promote the growth of lateral branches, inhibit the rise of the flowering position, and avoid the occurrence of empty and bare lower branch parts. Carrying out appropriate pruning twice in summer and winter can make the branch clusters well ventilated and lit, enhance light, and concentrate nutrients on flowering branches. Rose bushes with particularly vigorous branches and leaves may not necessarily produce many fresh flowers, because most nutrients are consumed in vegetative growth. Conversely, if a bush blooms too much and nutrient consumption is excessive, it is easy for the bush to weaken in growth vigor, seriously affecting the fresh flower yield of the following year.

4. Pruning of roses

The principles of rose pruning and training are: if the flower bushes are planted in the bead-chain style, 15-20 thick and strong branches can be selected and retained per bush; if planted in the hedge style, a certain distance should be kept between branches, and crossing branches, densely growing branches, overlapping branches, slender branches, lodged branches, dead branches and pest- and disease-damaged branches should be cut off, so that nutrients are concentrated on flower branches and flowering branches can grow strongly. Pruning should be combined with the specific situation, mainly light pruning, removing unneeded branches. If too many branches are pruned at one time, it is unfavorable for producing and storing nutrients, destroys the balance between the aboveground part (branches) and the underground part (root system), and affects the growth of flower branches and the fresh flower yield of the following year. After pruning, fertilizer and water management must be strengthened, otherwise the purpose of the new shoots that sprout will not be achieved. The pruning methods are as follows:

(1) One-time renewal method. Around Frost's Descent, cut off all rose branches 5-6 cm above the ground, then cover the retained cut branches with fine soil and mound it into a steamed-bun shape. The following spring, many new tender branches grow from the rose roots. After the new shoots stop growing, cut off the overly dense and thin weak shoots. The retained branches should be evenly distributed in space, ventilated and exposed to light, and fertilizer and water management should be strengthened. In the third spring, the roses grow vigorously and the fresh flowers are abundant.

(2) Two-time renewal method. Cut off half of the aging branches of the bush, use the retained branches to produce fresh flowers, and after the roses bloom and are harvested, renew the retained branches, so that fresh flower yield will not be reduced because of pruning branches.

(3) Year-by-year renewal method. This method is relatively commonly used in various places for rose pruning. Each year, according to the growth of the rose branch clusters, timely cut off dead branches, slender branches, aging branches and pest- and disease-damaged branches, prompting the branch clusters to produce new branches each year, maintaining vigorous growth of the branch clusters, keeping yield from declining, and also achieving the purpose of renewal and rejuvenation.

[Precautions]

(1) For grafted rose seedlings, cut off all branches on the rootstock. Pruned branches should be reasonably distributed, not leaning to one side. Appropriately cut off aging branches and renew and rejuvenate them in time. When pruning one-year-old branches, retain outward-facing buds to promote the formation of large numbers of flowers on lateral branches. Leave a stub of 1-1.5 cm above the outward-facing bud to avoid the branch drying downward and affecting the growth of the bud below the cut.

(2) When pruning and training, for upright, thick and strong water sprouts, cut them at 80 cm above the ground to promote the production of lateral flowering branches. Do not prune too late, otherwise they will not sprout and grow branches. For aging branches, cut them off 5-6 cm above the ground to make them sprout new branches. When pruning, select and retain plump buds on the branches so as to cultivate strong branches.

(3) The time for pruning and training should be after rose harvesting is completed. Because from the end of flower harvesting to rose dormancy and leaf fall, this period is the rose growth and development period and requires large amounts of nutrients. If allowed to grow naturally, nutrient consumption will be increased, which is unfavorable for the growth of flowering branches the following year and affects fresh flower yield.

(4) The blades of pruning tools must be kept sharp, and the cuts should be smooth and neat, avoiding tearing the cuts and affecting sprouting and growth.

According to relevant experiments, pruning roses has many advantages. Taking a six-year-old rose bush planted in the bead-chain style as an example, under the same management conditions, a pruned rose bush has thick and strong branches distributed evenly, is ventilated and exposed to light, grows vigorously, has large leaves and verdant color, and the branches form large flowers in large numbers with high oil yield, producing 300-400 kg of fresh flowers per mu. An unpruned bush easily declines, with densely grown and crossing branches, poor light penetration and ventilation, many slender branches, small leaves, yellow color, small flowers, few flowers, poor quality, low oil yield, and frequent pest and disease problems, producing only 15-40 kg of fresh flowers per mu.

Pest and disease control

In the rose production process, pest and disease control adopts the prevention and control principle of "prevention first, integrated control." Once pests and diseases occur, cut flower quality will be reduced and economic benefits affected. Regularly check the isolation measures of the greenhouse to control pest invasion; clean the greenhouse film in time, and ventilate and dehumidify promptly as temperature and humidity change. When watering and fertilizing, do not splash water or fertilizer onto the leaves, and avoid using sprinkling irrigation to supply water. Timely remove weeds inside and outside the greenhouse so as not to provide overwintering sites for pests. Timely pull out infected plants and remove diseased leaves, while applying chemical treatments to control the further spread of the disease. After each flower harvest, the plants should be sprayed with a protective agent to prevent diseases from invading through wounds. When using chemical pesticides for control, use fumigation (sulfur fumigation, chlorothalonil compound fumigation) as much as possible. When using spray methods, also choose pesticides that do not easily leave stains, such as insecticides and fungicides in formulations such as suspension concentrates, aqueous solutions and emulsifiable concentrates.

Harvesting of rose cut flowers

The harvesting time for cut roses can be from 7:30-10:30 every morning and after 16:30 in the afternoon. Before harvesting flowers, the harvesting buckets must be cleaned and then filled with preservative solution and placed in the harvesting shed, to ensure that within 5 minutes after harvest the cut flowers are inserted into the preservative solution, and the cut flowers are transported to the cold storage as soon as possible for precooling, with the cold storage temperature at 5 plusmn 1 degC. The harvesting standard must be determined according to the cut flower variety, market entry, transport distance and time, etc. Flower opening index:

1. The sepals are slightly loose and the petal tips are still tightly closed, suitable for long-distance transport and storage.

2. The sepals are loose, suitable for long-distance transport.

3. The petals extend beyond the sepals, and can be used for both long-distance and short-distance transport.

4. The outer petals begin to loosen, suitable for short-distance transport and nearby wholesale sales. In addition, according to variety characteristics and harvesting season, the harvesting standard can be appropriately adjusted. In summer when temperatures are high, harvest appropriately earlier; in winter when temperatures are low, harvest at a greater degree of maturity. Harvesting too early or too late will affect the vase life quality of cut flowers.

High-yield greenhouse cultivation techniques for rose cuttings

Rose planting methods and cultivation techniques

Rose cultivation techniques

Soil preparation

Cultivation method and planting

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