1. Introduction
Reproduction is a natural phenomenon that can continue offspring. Garden plants are of various types and come from a wide range of sources, so the reproduction methods are also relatively complex. In summary, they can be divided into sexual reproduction, asexual reproduction, tissue culture, etc.

2. Sexual reproduction
The method of reproducing offspring through seeds is called sexual reproduction, also known as seed reproduction. That is, sowing seeds to obtain seedlings. The advantage is that more plants can be obtained in a smaller area in a shorter time. The method is simple, low-cost, and suitable for large-scale professional production and transportation. It conforms to the natural growth and development laws of plants, with complete root systems and strong growth. The disadvantage is that it takes a long time from sowing to harvesting seeds and cross-pollinated flowers are prone to mutation, making it difficult to maintain the excellent characteristics of the original variety.

sowing

1. Seed quality and storage
To obtain excellent offspring, you must select excellent seeds. Excellent seeds should be well-developed, large and vigorous, with a high germination rate and germination potential. The seeds should be of high purity without hybrids, impurities, pathogens and eggs, or processed without pathogens and eggs. To obtain improved varieties, all introduced flower seeds must be inspected for seed quality and source identification.

In order to maintain the germination potential, germination rate and life of seeds, it is best to dry and seal them, and place them in a dry, low-temperature (1-5 degrees) and ventilated place to reduce the physiological activity of seeds, extend the life of seeds and maintain high vitality. The principle of seed storage is to keep the metabolism of seeds in the weakest state. The main external factors affecting it are humidity, temperature and air. Therefore, under the condition that it does not affect the vitality of seeds, the moisture content of seeds is lower, which is the so-called standard moisture content for seed storage. Different varieties have different standard moisture contents. Generally, the storage temperature of seeds should be below 15 degrees, the suitable temperature is 0-5 degrees, and air circulation is appropriate.

2. Seed treatment

Seed treatment can promote early germination of seeds and uniform emergence of seedlings. Due to the different seed sizes, seed coat thicknesses, and properties of various garden plants, different treatment methods should be used to treat them differently.

(1) Seeds that are easy to germinate Marigold, pinnate vine, and some cactus seeds are easy to germinate and can be sown directly or treated with cold or warm water. Soak the seeds in cold water (0-30℃) for 12-24 hours or in warm water (30-40℃) for 6-12 hours to shorten the seed expansion time and speed up the emergence of seedlings.

(2) Seeds that are difficult to germinate. Generally, large seeds are difficult to germinate, such as pine seeds, cannas, strelitzias, lotus, etc. Their seed coats are thick and hard, making it difficult for them to absorb water. For these seeds, you can scratch or wear the seed coat with a knife before soaking. When treating a large number of seeds, you can soak them in dilute sulfuric acid. Be sure to do a good experiment before use and master the time. As soon as the seed coat becomes soft, immediately rinse the sulfuric acid off the seed coat with clean water to prevent the sulfuric acid from burning the embryo.

(3) Seeds that germinate slowly

Some flower seeds, such as coral bean, asparagus fern, Clivia, honeysuckle, etc., are very slow to germinate and should be germinated before sowing. Soak the seeds in warm water before germination. After the seeds swell, spread them on gauze, cover them with wet gauze, put them in a constant temperature box, maintain a temperature of 25-30℃, rinse them with warm water and gauze once a day, and sow them immediately after the seeds germinate.

(4) Seeds that need to break dormancy

Some seeds cannot germinate normally even if they are given suitable conditions such as water, temperature, oxygen, etc. during dormancy. They must go through the vernalization stage at low temperatures before they can germinate, bloom and bear fruit, such as peach, apricot, lotus, rose, azalea, white magnolia, etc.

For dormant seeds, low temperature stratification can be used. The flower seeds are buried in moist plain sand in layers and then placed in a 0-7℃ environment. The stratification time varies depending on the species, and is generally about six months. For example, azalea and elm-leaf plum need 30-40 days, crabapple needs 50-60 days, peach, plum, plum, etc. need 70-90 days, wintersweet and white magnolia need more than three months, and red pine needs more than six months. After stratification, the seeds can be taken out, the sand can be sieved off, and they can be sown directly or sown after germination.

3. Sowing period and pre-sowing preparation

(1) For garden plants with different sowing periods, the sowing period should be selected according to the needs and their own biological characteristics, and the sowing period should be selected according to environmental conditions.

With flexible control of the parts and timely sowing, not only the seedlings emerge evenly and the germination rate is high, but also the needs of flower applications in different periods can be met.

Annual grass flowers are mostly sown in spring, generally from early April to early May in the north, from early March to early April in the Central Plains, and from late February to early March in South China. In addition, sowing can be advanced or delayed according to market needs, such as May Day and National Day. Biennial grass flowers are generally sown after the beginning of autumn, mostly in early and mid-September in the north, and in mid-to-late September and early October in the south.

Seeding period of outdoor woody flowers Most of these flowers and trees are large seeds, such as apricot, privet, white wax, plum, peach, etc. Most of them are autumn sown from early September to late October. They can pass the vernalization stage in the field and emerge neatly in the second year. Do not sow too early, otherwise the temperature in autumn will be high and the seeds will germinate in the same year and be easily damaged by frost. Seeds that have been stratified can be sown in spring and sown immediately after the soil surface thaws, so that the seedlings can be lignified before the arrival of the dog days, so as to avoid withering of seedlings due to heavy rain and high temperature.

Greenhouse flowers are mostly evergreen plants from tropical and subtropical regions, such as cacti and evergreen foliage plants. Seed germination is mainly affected by temperature. In the greenhouse, sowing can be carried out all year round, and the sowing time can be arranged according to market needs. Greenhouse sowing should be kept at a relatively constant temperature as much as possible. If the temperature difference between day and night is too large, sowing often fails.

Most lawn plants can be sown in early spring or autumn, but autumn is generally the best time to sow. Water the ground thoroughly before sowing. Summer is also a good time to sow, but high temperatures can cause poor growth of seedlings, and overgrowth of weeds can sometimes lead to sowing failures.

(2) Preparation before sowing

a) Soil preparation: The soil for seedling cultivation is the basis for providing the water, nutrients and air needed for the growth and development of flower seedlings. High-quality bed soil should be fertile, loose and fine. The requirements for the nutrient soil for small seeds are stricter, and the soil particles should be small. The formula of the nutrient soil is as follows:

Formula ⑴ - 50% garden soil (pond mud), 25% wood ash (or coconut bran, peat), 25% decomposed chicken manure (or other decomposed organic fertilizer).

Formula (2) - 40% garden soil (pond mud), 25% wood ash (or coconut bran, peat), 10% fine sand, 25% decomposed chicken manure (or other decomposed organic fertilizer).

b) Soil disinfection

For disinfection of 65% mancozeb powder, use 60 grams per cubic meter of bed soil. After mixing, cover it with a film for 2-3 days. After removing the film, it can be used only after the smell of the medicine has dissipated. It has a certain preventive and therapeutic effect on diseases.

Chloropicrin disinfection has a preventive effect on all soil-borne pests and diseases. The optimum temperature for the use of this drug is 15-20℃, and the bed soil should be slightly moist. Before using the drug, pile the bed soil into a 30 cm high earthwork, insert a small hole every 30 cm, and the hole depth is 10-15 cm. Pour 5 ml of chloropicrin into each small hole, then seal the hole, and then seal the pile with film. After about 7-10 days, remove the film, fully overturn the soil pile, let the drug smell evaporate, and the bed soil can be used after 7-10 days.

Methyl bromide disinfection has a certain killing effect on soil-borne pests and diseases. Pile the bed soil into a 30 cm high strip. After the surface is leveled, place a small basin in the middle of the soil pile, put in methyl bromide and cover it with a lid with holes. The dosage of the medicine is 100-150 grams per square meter of bed soil. Use a small arch shed to seal it to prevent the medicine from overflowing after volatilization. After 10 days, remove the film and turn over the bed soil. After another 2-3 days, the bed soil can be used after the smell of the medicine evaporates.

c) Seed disinfection Seed disinfection can effectively prevent seedling diseases, such as damping-off and damping-off, to increase the seedling rate. Common disinfection methods include the following:

The dosage of carbendazim powder and trichlorfon powder for seed disinfection is 0.2-0.3% of the seed weight. It is best to mix it dry so that the seeds are evenly coated with the medicine and it is less likely to cause drug damage.

Formalin solution disinfection usually uses 200 times 40% solution to soak seeds for 10-15 minutes, remove and rinse, and sow after drying.

Disinfection with copper sulfate solution: Soak the seeds in 1% copper sulfate solution for 5 minutes, remove and rinse, dry in the shade and then sow.

Potassium Permanganate Disinfection: Soak the seeds in 0.5% potassium permanganate solution for 2 hours, remove and rinse, dry in the shade and then sow.

3. Sowing methods and procedures

(1) Sowing method　

Broadcasting is to spread the seeds evenly on the seedbed. This method is suitable for small seeds. If the seeds are too small, they can be mixed with an appropriate amount of fine sand before sowing. Broadcasting has a large sowing volume, more seedlings, and saves labor and land, but it uses a large amount of seeds and is more difficult to manage.

Spot sowing is done by digging holes at a certain spacing between plants and rows. It is suitable for large seeds and rare seeds, such as ginkgo, pine, rare cactus seeds, etc. Spot sowing is labor-intensive and time-consuming, but the seedlings are strong and easy to manage.

Row sowing is to sow seeds in furrows at a certain row spacing. It is suitable for medium and small seeds. The row spacing and sowing width depend on the situation. Row sowing uses less seeds and is easy to manage. This method is mostly used for woody seedlings.

(2) Seeding procedure

Sowing: Use appropriate sowing methods according to seed size and specific conditions.

Covering with soil: Covering with soil after sowing should be done in time, and the thickness of the covering soil should be 2-4 times the diameter of the seeds. Some very small seeds, such as begonias, gloxinia, and some cactus seeds, do not need to be covered with soil, but they must be covered with glass or plastic film to keep moisture after sowing. Loose soil or fine sand, plant ash, coconut bran, peat, etc. should be used for covering soil. Heavy clay soil should not be used.

Pressing down Pressing down makes the seeds closely bond with the soil, allowing the seeds to fully absorb water and swell, thus promoting germination. Pressing down should be done when the soil is loose and the upper layer is relatively dry. Pressing down should not be done when the soil is heavy and sticky, so as not to affect seed germination. Pressing down should not be done when the seeds are being sown for germination.

After sowing, cover with film, shade net, etc. to maintain soil moisture, prevent rain and regulate temperature, but the covering should be removed in time after the seedlings emerge.

e) Watering Before sowing, the nutrient soil should be filled with enough water. No watering is required before the seedlings emerge. If some seeds have a long germination period and need watering, spray irrigation should be carried out to avoid direct spraying with large amounts of water to prevent the seedbed from becoming hardened. If the seeds are sown in pots, the immersion method can be used until the soil surface of the pot is moist.

4. Management after sowing

Water, atmosphere and temperature are the main factors that affect seed germination. Under the conditions of suitable temperature and good sowing soil, seedlings can emerge as long as they are properly managed. From the time of sowing to before and after germination, the soil should be kept moist and water should be evenly supplied. Sowing in containers and keeping them moist with glass can generally maintain germination. If some seeds need 7 days to germinate, or the weather is particularly dry, water can be absorbed and supplied again. It is advisable to open the glass in the morning and evening to allow ventilation. In early summer or even summer, the temperature is high and the seeds germinate quickly. You can leave the glass uncovered. This can prevent the phenomenon of rotten seedlings and fallen seedlings caused by excessive temperature and humidity. In autumn and winter, the temperature is low and the seed germination time is slow. The glass must be covered during the day to effectively prevent water evaporation. Temperature control is mainly in autumn, when the temperature is often low and the germination time is too long, affecting the germination rate. Therefore, effective insulation must be carried out, and even heating devices must be installed to meet the temperature required for seed germination at any time. After the seeds germinate, the covering should be removed immediately, and the seedlings should be exposed to light gradually. After a period of training, they should be fully exposed to the sun. Fertilize once after the true leaves appear. When the seedlings grow 4 to 5 true leaves, they can be transplanted, commonly known as rice seedlings. Some seedlings can be transplanted when they grow 1 to 2 true leaves in the pot. The pots used for transplanting are the same as those used for sowing.

3. Asexual Reproduction

Asexual reproduction is a method of multiplication under artificial assistance using the regenerative ability of plant vegetative bodies, also known as vegetative reproduction. Common asexual reproduction methods for flowers include cuttings, grafting, division, layering, etc. Its characteristics are that it can maintain the excellent traits of the mother plant, and has a short growth cycle, early flowering and fruiting, etc. The disadvantage is that some flowers are not as good as seedlings in growth and vitality.

Cutting propagation

Cuttings are one of the important means of flower propagation. Due to the application of some scientific and technological means in flower production, almost all plants, from one- and two-year-old herbs, cacti to woody plants of the Coniferaceae family, can survive by cuttings. Cutting propagation is to insert the nutritional organs of plants such as roots, stems, and leaves into the substrate to make them take root and grow into complete plants. Its advantages are sufficient propagation materials, large seedling production, fast seedling formation, early flowering, and the ability to maintain the inherent excellent characteristics of the original variety. It can obtain seedlings that are completely consistent with the genetic traits of the mother plant. It is suitable for large-scale production in flower fields and small-scale reproduction in families. The disadvantage is that the cutting seedlings obtained have poor root systems and cannot form taproots. Their lifespan is shorter than that of sown seedlings, and their resistance is not as good as that of grafted seedlings.

1. The method of cutting propagation can be divided into branch cutting, leaf cutting, leaf bud cutting, bud cutting and root cutting according to the different cutting materials. They are suitable for use in cuttings of various garden plants.

(1) Herbaceous cuttings Among herbaceous cuttings, chrysanthemum is the most commonly used. The cuttings of herbaceous flowers should be selected from the branches at the bottom of the plant. For example, the best cuttings for chrysanthemum are the young shoots that grow directly from the roots, which are generally about 6 cm in length. The tissue should be of moderate maturity. If it is too tender, it will easily rot, and if it is too old, it will take time to root. When cutting the cuttings, it should be done below the nodes, because the roots grown from the adventitious buds on the nodes are better than the roots grown from the callus tissue of the incision.

Leaf cuttings use the artificially created wounds at the leaf veins to produce callus tissue, which then sprouts adventitious roots or adventitious buds to form a new plant.

Flat-lay method: Take a mature leaf of Begonia or Gloxinia, cut off the petiole, first cut the main veins on the back of the leaf with a blade, then lay it flat on the sand, and then press a small stone on the leaf surface to make the main veins and the sand surface fit closely, while maintaining humidity. After about a month, roots sprout from the cut, new leaves also emerge from there, and old leaves gradually wither. To reduce evaporation, the edges of the leaves can be cut off (see Figure 3-1-1).

The direct insertion method is to cut the leaves of the snake plant into small sections, each section is 4-6 cm, and then shallowly inserted into plain sandy soil. After a period of time, fibrous roots will appear in the wounds at the base and underground rhizomes will grow. A new plant will grow from the apical buds of the rhizomes (see Figure 3-1-2).

For petiole insertions, such as African violets and Gloxinia, you can take the leaves with petioles and insert them into plain sand and maintain appropriate humidity. This method will cause rooting quickly, and new plants will grow from the petioles. The seedlings grown by this method are stronger than those grown by the flat placement method.

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Figure 3-1 Schematic diagram of leaf cuttings, leaf bud cuttings, and root cuttings of flowers

1. Begonia flat plug 2. Tiger tail orchid leaf plug 3. Rubber leaf bud plug 4. Camellia japonica bud plug

5. Chrysanthemum leaf buds 6. Hydrangea leaf buds 7. Peony and peony root buds

Scale cuttings: Lily scales can be used for propagation by cuttings. After the lilies have faded, dig out the bulbs, dry them for several days, peel off the scales, and insert them one by one into the sand bed. After 40-60 days, small bulbs will be produced at the base of the scales.

f) When using softwood cuttings for herbaceous flowers, the tip of the stem with terminal buds is often used as the cutting material to facilitate rooting and growth. For some plants that are not easy to sprout side buds, terminal buds are especially required. Among herbaceous plants, chrysanthemums, carnations, dahlias, spathiphyllums, petunias, salvias, coleus, begonias, etc. can all be propagated by cuttings (see Figure 3-2-1, 2).

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Figure 3-2 Schematic diagram of softwood cuttings of several flowers

1. Geranium 2. Chrysanthemum 3. Rose 4. Cacti

g) Leaf bud insertion Leaf bud insertion is when the axillary buds are mature and full but not yet sprouted, they are cut off together with a small section of the branch at the node, and then shallowly inserted into the sand bed with the tip of the axillary bud exposed above the sand surface. When adventitious roots are produced at the base of the petiole, the axillary buds begin to sprout and then grow into new seedlings (see Figure 3-1-5).

h) Root cuttings Some flowers and trees with large fleshy fibrous roots or taproots, such as peony, can be propagated by root cuttings, relying on the adventitious buds produced on the roots to grow new plants. Root cuttings are often carried out in conjunction with transplanting or dividing the mother plant in spring and autumn. It is advisable to use roots with a thickness of 0.5-1.5 cm, cut into root segments of about 10 cm, and the thick roots can be planted obliquely into the soil, while the thin roots should be placed flat on the surface of the seedbed and covered with 1 cm of fine sand (see Figure 3-1-7).

(2) Woody cuttings The main cutting method for woody flowers is branch cuttings, which are divided into softwood cuttings and hardwood cuttings. They are introduced as follows:

Softwood cuttings, also known as green branch cuttings, are cuttings made from semi-lignified branches with leaves. They are carried out in summer and autumn when the plants are growing vigorously. It is advisable to pick semi-lignified branches that are fully grown in the current year, remove the tender parts at the top, cut into about 10 cm, keep 1-2 leaves on the top, and cut off 1/2-2/3 of the leaves. Then use a sharp knife to flatten the base 1.5-3 mm below the node, without causing phloem peeling, and then insert it into a moist substrate. Pay attention to moisturizing the cuttings to prevent water loss and wilting, which will cause the cuttings to fail (see Figure 3-2-3).

Cuttings for hardwood cuttings should be cut from one- or two-year-old fully lignified branches, with leaves and petioles cut off. Hardwood cuttings are usually carried out during the dormant period from leaf fall to next year's budding, mostly in autumn in the south and spring in the north. Cuttings are usually cut into 10-20 cm long, with the cut 0.5-1 cm away from the top bud to protect the top bud from dehydration and drying. Most of the cuttings can be inserted into the substrate, leaving only 1-2 side buds on it. After cutting, shade is generally not required, and special treatment can be given to the branches during cutting, such as cutting, bringing soil balls, bringing a small section of side branches (with heels), etc. (See Figures 3-3-1, 2, 3).

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Figure 3-3 Several special hardwood cutting methods

1. Split insertion 2. Soil ball insertion 3. Heel insertion

In addition, among woody plants, rubber trees can also be cut by leaf cuttings (see Figure 3-1-2), camellia, peony, azalea, osmanthus, rubber trees, gardenia, etc. can be cut by leaf bud cuttings (see Figure 3-2-3, 4, 6), and Chinese toon, lilac, crabapple, wisteria, etc. can be cut by root cuttings (see Figure 3-1-7). The operation method is the same as the previous section.

(3) Cacti and succulents cuttings

The cuttings of cacti and succulents are different from those of herbs and woods, and have their own particularities. If the technique is not mastered well, they are very easy to rot. The cuttings of cacti and succulents use the characteristics of their vegetative organs with strong regeneration ability and the ability to produce adventitious buds or adventitious roots. Cut the stem nodes or part of the stem nodes, as well as the bulblets and adventitious buds produced, and insert them into the substrate to make them take root and become new plants.

Types and methods of collecting materials

Some species are easy to breed baby balls, and the baby balls have already taken root on the mother plant. In this way, you only need to break off the baby balls and plant them directly. For example, the Changsheng ball of the genus cactus belongs to this kind of situation.

Some species are also easy to breed baby balls, but they do not take root on the mother plant, so they can be broken off and cut for cuttings, such as Zisun Ball, Hong Xiaomachi, Yingguanyu, etc.

For species with fleshy modified stems in node shape, cuttings can be cut according to the nodes, such as Christmas cactus, fairy finger, epiphyllum, bachelor tree, etc.

The spherical species that are not easy to reproduce bulblets and the columnar species that are not easy to branch need to be topped at the beginning of the growing season, that is, the plant is cut off at the appropriate position, the upper part of the plant is dried and then cut, and the lower part of the plant is strengthened to promote the reproduction of bulblets. Such as golden barrel cactus, snow light, etc.

For some species, you can choose strong leaves for leaf cuttings, such as Kalanchoe chinensis, Flos radiata, Eclipta tenuifolia, Corn Stone, Jade Tree, etc.

Some species of the genus Kalanchoe in the Crassulaceae family, such as the radish plant, can grow bulbils at the edges of the leaves. These bulbils can be removed and directly inserted into pots to grow into new plants.

2. Environmental conditions for rooting of cuttings

Cuttings are easier to root when the temperature reaches 20-25℃, but for species of the genus Coleus native to tropical areas, a slightly higher temperature is preferred.

Humidity: Since cactus plants contain more water, they do not require very high humidity when cutting, especially the cutting medium should not be too wet, otherwise it will easily rot.

After sun cuttings, appropriate shade should be provided to avoid direct sunlight.

The most suitable substrate is a material with good permeability and moisture retention. It can be directly cut into soil with good permeability. Other commonly used cutting materials include river sand, rice husk ash, peat, leaf mold, sawdust, coal ash slag, etc., which can be used alone or in combination.

3. Cutting period

In southern China, cuttings can be taken all year round, but spring and autumn are the best. It is best not to take cuttings in summer, because most species are dormant in summer, and the temperature is high and the humidity is high, making them prone to rot. Pay attention to heat preservation when taking cuttings in winter. In the north, cuttings can be taken in spring.

4. Precautions and management after cutting

When cutting scions, use a stainless steel knife and the cut surface should be smooth. When cutting scions from diseased plants, the knife should be disinfected with alcohol.

The mother plant that provides cuttings should be selected with strong growth. Those with weak growth are generally not suitable for cuttings.

Cuttings cannot be inserted immediately after cutting, they must be dried before insertion, and thicker scions should be dried for a few more days. When cutting, it should not be too deep, and it is better to have the base slightly inserted into the substrate.

For some species that are difficult to root, after the incision has dried up, you can soak it in a 250ppm naphthaleneacetic acid solution for 4 hours before grafting, which has a certain effect on promoting rooting.

After the cuttings have taken root, transplant them into pots in time and keep the culture soil slightly moist. Do not water them within a few days after potting them and provide appropriate shade (see Figure 3-2-4).

(ii) Grafting

Grafting is a major method of garden plant breeding technology. It uses reproductive bodies (stems, buds, balls) to combine two different plants together to form an independent new individual. The reproductive body used for grafting is called "scion", and the plant receiving the scion is called "stock".

1. Advantages and disadvantages of grafting

Advantages of Grafting

(1) Overcoming the disadvantage of some plants being difficult to propagate; some excellent varieties of garden plants that are difficult to survive by cuttings or layering, or plants that cannot maintain their excellent characteristics by sowing can be propagated by grafting, such as dwarf ornamental peach and double-petal plum.

(2) Maintain the excellent traits of the original variety; since the reproductive body of the scion has stable traits, it can maintain the excellent traits of the plant, and the rootstock generally does not affect the heredity of the scion.

(3) It can improve the resistance of the scion variety. The rootstock used for grafting has many excellent characteristics, which in turn affect the scion, making the scion's resistance to diseases and pests, cold resistance, drought resistance, and thinness resistance improved. For example, peony grafted onto peony, chrysanthemum grafted onto white wormwood or Artemisia annua, and azalea grafted onto Rhododendron hairy white can all improve their adaptability.

(4) Early flowering and fruiting: Since the scion is already in the mature stage when grafted, the rootstock has a strong root system and can provide sufficient nutrition, enabling it to grow vigorously and facilitating nutrient accumulation. Therefore, grafted seedlings grow stronger than seedlings or cuttings and flower and fruit earlier.

(5) Changing the shape of the plant; by selecting rootstocks, seedlings of different plant shapes can be cultivated, such as using a dwarf rootstock to graft a peach tree onto a peach; using an arborescent rootstock to graft a willow tree; using a rose to graft a rose to produce a tree rose, etc., so that the grafted plants have special ornamental effects.

(6) Seedlings mature quickly. Since the rootstock is relatively easy to obtain and the scion only uses a small branch or a bud, the breeding period is short and a large number of seedlings can be produced.

(7) Improve ornamental value and promote variation. For cactus plants, after grafting, the rootstock and scion influence each other, and the scion is more ornamental than the mother plant. Some grafted species have mutated and produced new species due to the mutual influence of genetic material. The famous dragon and phoenix peony is a mutated variety that occurred when the red peony was grafted onto the hyacinthus.

Disadvantages of Grafting

(1) Limitations: Grafting is mainly limited to dicotyledons, while monocotyledons are more difficult to survive, and even if they survive, their lifespan is short.

(2) It is labor-intensive and time-consuming; grafting and management require a certain amount of manpower and time, and the cultivation of rootstocks also requires a certain amount of human resources.

(3) Highly technical: Grafting is a highly technical job that requires the training of skilled workers.

2. Commonly used rootstocks and suitable seasons for grafting

(1) Commonly used rootstock types

The sources of rootstocks are: first, collected wild seedlings; second, artificially cultivated varieties with strong resistance. The commonly used rootstocks are shown in the following table:

Table 2-1 List of commonly used rootstocks

Scion

Kinuta wood

Scion

Kinuta wood

Peach

Birthday Peach

Michelia

Yellow orchid, magnolia

Sophora japonica

Sophora japonica

Golden cypress

Platycladus orientalis

plum bossom

Prunus armeniaca, Peach

White Orchid

Yellow orchid, wood pen

Katsura flower

Ligustrum lucidum, wax

Magnolia grandiflora

Yellow orchid, magnolia

Gold Tachibana

Other citrus

Green

Juniper, Platycladus orientalis

Purple clove incense

Ligustrum lucidum, wax

Peony

Peony

Five-needle pine

Black pine

Cypress

Juniper, Platycladus orientalis

Western Azalea

Azalea, Rhododendron

Wintersweet

Other Wintersweets

Chrysanthemum Flower

Green, yellow and white wormwood

Cherry blossoms

Cherry tomentosa

Cactus

Measuring ruler, grass ball

Magnolia

Mulan

Yunnan Camellia

Wild Camellia

Rose

rose

(2) Suitable season for grafting

Grafting can be done in spring, summer and autumn, but spring and autumn are the best. Some species can be grafted in the greenhouse all year round. However, the types of flowers and trees and the methods of grafting vary. Generally, branch grafting is done before the sap begins to flow, and bud grafting is best done in late summer and early autumn when the axillary buds of the scion have developed and become fully developed. Chrysanthemums can be grafted during their growth period, and cacti can be grafted all year round.

(3) Tools and materials used for grafting

Grafting materials rootstock and scion are prepared before grafting.

Tools for grafting include pruning shears, branch grafting knives, bud grafting knives, hand saws, blades, etc.

Most woody plants use plastic film as the binding material, which has the advantages of good elasticity, water retention, and ease of use. In addition, cactus grafting requires cotton thread, cotton balls, etc. for binding and fixation.

Waxing wax can effectively prevent the wounds of flowers and trees from drying out and necrosis after grafting. Waxing wax can be divided into two types: solid wax and liquid wax. The method of making solid wax is to mix rosin, beeswax and animal oil in a ratio of 4:2:1. First melt the animal oil, then add rosin and beeswax into the oil, and pour it out after melting. It becomes solid after cooling and needs to be heated and softened when used. Liquid wax is made of rosin, animal oil, alcohol and turpentine as raw materials, and is prepared in a ratio of 10:2:6:1. First put the rosin and animal oil into the pot and heat them, take them out after melting, add alcohol and turpentine when they are slightly cool, stir evenly, and then put them into the bottle and seal them for storage.

3. Grafting propagation technology of flowers

In order to improve the survival rate of grafting, people use different grafting methods according to different plant characteristics and different periods. There are four main types of grafting: branch grafting, bud grafting, root grafting, and flat grafting. The rootstock is the basis of grafting. The growth of the rootstock and its affinity with the scion will affect the survival of the graft. Generally, the rootstock must be cultivated in a nursery to meet the needs of grafting and reproduction.

Choice of rootstock

Since the rootstock has a great influence on the scion, and there are many types of rootstocks to choose from, the selection should be based on local conditions and time. The selection of rootstocks should meet the following conditions:

Strong affinity with scion. Generally, plants of the same genus have strong affinity, such as plum blossom can be grafted on apricot rootstock, wild plum rootstock, mountain peach, and hairy peach;

They have strong adaptability to the cultivation area, climate, soil and other environmental conditions. For example, the hairy peach is resistant to moisture but weak to cold, while the wild peach is the opposite. Therefore, when choosing plum rootstocks, the south chooses the hairy peach, while the north mostly chooses the wild peach.

It can have a positive impact on the growth, flowering, fruiting and lifespan of the scion. For example, if the plum blossom is grafted onto an apricot or plum rootstock, it will have a longer lifespan than if it is grafted onto a wild peach or hairy peach rootstock, but it will bloom later.

The source is sufficient and easy to reproduce, such as the rhododendron or rhododendron rootstock used by the western azalea, which has a wide source and a large number of wild ones, which can meet the needs of grafting;

It has good resistance to pests and diseases, drought, flood, low temperature, etc. Wild rootstocks generally have strong resistance, such as mountain peach, wild plum, azalea, etc.

Cultivation of rootstock

Rootstocks can be propagated asexually or sexually. However, it is best to use sowing to cultivate seedlings, because seedlings have strong resistance to adverse environmental conditions and long life. In addition, their true age is young and will not change the inherent characteristics of the scion of excellent varieties.

Methods and steps of grafting

(1) Steps of cutting method (see Figure 2-1)

Generally, one-year-old branches are used as scions. The scion length is 5-10 cm, and each stem segment contains 2-3 buds. Then use a grafting knife to cut two symmetrical bevels of different sizes at the base of the scion. The inner cutting depth should not be too deep. Most of the wood part can be cut off. One side is about 2 cm long and the other side is about 1 cm long. The knife should be sharp and the hand should be steady to ensure that the cut surface is flat and smooth. It is best to cut it in one go.

To cut the rootstock, cut it short 20 cm from the ground and trim it flat. Then, according to the thickness of the scion, choose a suitable position on the north side of the rootstock cross section and use a cutting knife to make a crack from top to bottom, about 2.5 cm deep. Be careful to use a sharp blade to ensure that the cut surface heals.

Insert the cut scion with the long cut surface inward into the incision of the rootstock, and align the cambium on both sides. The upper end of the scion should be exposed about 0.2 cm, which is commonly known as "white exposure", which is conducive to the combination of the rootstock and scion.

Use plastic strips to tie the joints tightly. For some younger scions, in order to prevent the scions from drying out before the joints heal, it is best to cover the scions and the cuts with a small plastic bag to reduce water loss, and remove the bag after the scions have grown new growth.

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Figure 2-1 Steps of splicing

1. Cut the scion 2. Cut the rootstock 3. Insert the scion binding

(2) Steps of the cleft grafting method (see Figure 2-2)

This method can be used when using a large mother plant as the rootstock, that is, when the rootstock is thick and the scion is thin. First, use a cleaver to cut vertically from the center of the cross section of the rootstock to a depth of about 3-4 cm. The cut surfaces on both sides of the lower part of the scion are the same length, cut into a wedge shape of 3-4 cm, and leave 2-3 buds on the upper part. In order to improve the survival rate, two scions are often inserted on both sides of the cut of the rootstock, and the cambium on the outside of the scion is aligned with the cambium on one side of the rootstock, and finally tied. Plastic strips can be used for tying, or wax sealing can be used.

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Figure 2-2 Steps of the cleft grafting method

1. Split the rootstock 2. Cut the scion 3. Insert the scion and tie it

(3) Steps of the docking method (see Figure 2-3)

Grafting is commonly used for evergreen woody flowers, such as Ligustrum lucidum grafted with Osmanthus fragrans, Platycladus orientalis grafted with Cypress, and Pinus thunbergii grafted with Pinus pentaphyllum. Grafting should be carried out during the peak growth season. First, move the cultivated one- or two-year-old rootstock to the vicinity of the mother plant for grafting. Select branches on the mother plant that are of the same thickness as the rootstock, cut them into a shuttle-shaped interface at the appropriate position, about 3-5 cm long and deep into the wood. The cut should be flat and the length of the cuts of the two should be the same, and then put them together. Align the cambium layers and then tie them. After the graft survives, cut the scion from below the interface and cut the rootstock branches from above the interface.

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Figure 2-3 Steps of the docking method

1. Cutting of stock and scion 2. Grafting and binding

(4) Belly grafting steps (see 2-4)

The cutting method of the scion is similar to that of the cut graft. One side of the scion is cut into a smooth cut surface at the bottom, 2 cm long, and the other side is cut into a 45° bevel. When cutting the rootstock, do not cut it off, just cut a 30° cut downward on the side close to the base to adapt to the size of the scion. Then insert the scion and tie it with plastic film. If it does not survive, you can re-graft it and cut the rootstock after the scion survives.

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Figure 2-4 Steps of abdominal grafting

1. Cut the scion 2. Cut the rootstock 3. Insert the scion 4. Tie it up

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Figure 2-5 Subcutaneous connection steps

1. Cut the scion 2. Cut the rootstock 3. Insert the scion 4. Tie it up

(5) Subcutaneous connection steps (see Figure 2-5)

Subcortical grafting is also called bark grafting. It is mostly used when the rootstock is large and the cortex is thick and easy to peel off. After cutting the rootstock at an appropriate position from the ground, cut a vertical slit in the cortex from top to bottom on the smooth side of the cross section, deep into the wood and about 3 cm long. The end of the scion is cut into a thinner tongue-shaped surface. With the large bevel facing the wood, slowly insert the cut scion into the cortex. To prevent the scion from tilting, the rootstock should be "white". Then tie it with plastic film.

Bud grafting methods and steps

(1) “T” type budding (see Figure 2-6)

For bud-cutting scions, you should select fully mature branches of the current year, select full axillary buds on the scions, and cut off the leaves on the scions, leaving only the petioles. Make a horizontal cut 0.4 cm above it, go about 0.1 cm into the wood, and then push upward from 0.5-0.6 cm below the axillary bud to the horizontal cut. Then remove the axillary buds, peel off the wood inside the buds, and then wrap the buds with a wet towel or put them in your mouth.

Cut the rootstock on the north side of the rootstock seedling between 10-15 cm from the ground, choose a smooth skin surface, cut the phloem into a "T" shaped incision, the length and width of which are slightly larger than the bud, and then use the bud grafting knife handle to pick open the bark.

Insert the bud into the cortex of the rootstock from above the "T"-shaped incision, so that the upper end of the bud coincides with the incision on the rootstock, but the bud and petiole on the bud must be exposed.

The plants are tied together with plastic film, leaving only the axillary buds and petioles exposed.

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Figure 2-6 “T” bud grafting

1. Cut the buds 2. Cut the rootstock 3. Insert the buds into the rootstock cortex 4. Tie

(2) Chip budding (see Figure 2-7)

This method is suitable for flowers and trees with thin stock seedlings and stock cortex that is not easy to peel off naturally. The survival rate of grafting is not as high as that of "T" bud grafting. There are three types of bud grafting: sheet bud grafting, ring bud grafting, and shield bud grafting. When cutting the bud, according to different methods and different scions, cut 0.1-1 cm above the bud, and then cut 0.5-0.8 cm below the bud. After removing the bud, cut an incision corresponding to the size of the bud at the appropriate part of the stock, then insert the bud into the interface, align the cambium on both sides, and finally tie or seal with wax.

Root connection

Root grafting is a grafting method that uses roots as rootstocks. It is usually performed in early spring or autumn when the plant is dormant. This method is commonly used for peony, rose, magnolia, trumpet creeper, etc. Generally, the roots of 1-2 year old seedlings are selected as rootstocks. The roots of the mother plant are dug up and the thicker root segments are selected, about 1-1.5 cm thick. Wash off the mud and cut it into a wedge shape with a clean sharp knife. Then cut the lower end of the scion into a corresponding shape. The scion is generally selected from the branches of the current year. When grafting, the cambium must be aligned. If the thickness of the scion and the rootstock is different, ensure that the cambium on one side is aligned with each other, then tie it with plastic tape and plant it in moist sand. Pay attention to shade and moisture during the maintenance process (see Figure 2-8).

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Figure 2-7 Several methods of chip budding Figure 2-8 Root grafting

1. Sheet budding 2. Ring budding 3. Shield budding 1. Scion 2. Rootstock 3. Grafting

Flat connection

This method is simple and convenient, easy to survive, and suitable for application on columnar and spherical species. The height of the rootstock can be flexibly controlled according to different requirements and personal preferences, but for spherical rootstocks, be careful to cut off the growth point when cutting horizontally, otherwise the scion will be pushed off and the grafting will fail. After cutting horizontally, cut off a part of the stem flesh and outer skin of the grass ball or hyacinthus at an angle of 30° downward. The purpose is that after grafting, the fleshy and slurry part at the top of the rootstock will shrink due to water evaporation, but the outer leathery cortex will not shrink. When the scion shrinks and sinks with the stem flesh of the rootstock, the hard skin of the rootstock will push the scion off, causing the grafting to fail. Cut the lower part of the scion horizontally and place it on the cut surface of the rootstock immediately after cutting. When placing it, make sure that the scion is partially in contact with the vascular bundle of the rootstock, and then tie it up and fix it.

When grafting golden button, the scion and the rootstock are often cut at an angle, with the length of the two inclined surfaces roughly the same, and then tied together. This method is called bevel grafting, but its operation method is similar to flat grafting and will not be described in detail. During grafting, both the rootstock and the scion should be cut with a sharp knife to make the contact surface smooth and clean. In the rainy season or when cutting scions of rotten plants, the grafting knife should be disinfected with alcohol before each cutting to avoid infection.

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Figure 2-9 Grafting methods of cactus plants

1. Butt joint 2. Miter joint 3. Wedge joint

4. Management after grafting

(1) Check survival

Generally, the survival of the branch grafting should be checked 3-4 weeks after grafting. If the scion has sprouted and is bright green, it is alive. The survival of the bud grafting should be checked 1 week after bud grafting. If the petiole retained on the bud piece falls off when touched, it indicates that the bud piece has survived. Otherwise, the bud piece has died and should be re-grafted below it.

(2) Loosening

After the grafting is successful, the scion can be untied one month after it survives. It is generally not advisable to untie it too early, otherwise the scion will not heal firmly and will fall off easily due to wind. It is also not advisable to untie it too late, otherwise the binding will be damaged and affect growth. Bud grafting is generally carried out in September. After the axillary buds survive, they will not germinate in the same year. Therefore, the binding material can be left untied and can be removed after the graft buds germinate in early spring of the following year.

(3) Cut the rootstock, remove the buds, and remove the suckers

The pruning of the rootstock depends on the situation. The rootstock can be pruned in the same year after the branch grafted seedlings survive. Most bud grafted seedlings can be pruned 1-2 times in the year of heading. In addition to removing the large number of buds produced by the rootstock, the excessive buds and root suckers on the scion should also be pruned to ensure the concentrated supply of nutrients.

3. Reproduction by meristem

Meristem propagation is one of the methods of plant vegetative propagation, which refers to the method of artificially separating the young plants grown from the plant body, such as suckers, from the mother plant and planting them separately to become independent new plants. Meristem propagation is the simplest and most reliable propagation method with a high survival rate, but a small amount of seedlings. Due to the different biological characteristics of flower plants, it can be divided into two methods: division and bulb division. The former is mostly used for flowering shrubs with strong clumping ability and perennial grass flowers with strong suckering ability, while the latter is used for bulbous flowers.

1. Division method: The division method produces seedlings quickly, and most of them can bloom in the same year.

Time of division

(1) Deciduous flowers and trees: The best time to propagate this type of flowers and trees is during the dormant period. In the north, it is usually done in early spring, and in southern China, it can be done after the leaves fall in autumn. Because the air humidity in the south is higher and the soil is generally not frozen, some flowers and trees can grow some new roots before winter, and the branches are not easily dried out in winter.

(2) Evergreen trees: These trees do not have a distinct dormancy period. However, regardless of the south or the north, most of them stop growing in the winter and enter a semi-dormant state, during which the sap flows slowly. Therefore, they are often divided in early spring.

Method of division

(1) Field flowers and trees Before the division of some species, the mother plant needs to be dug out from the field and as many roots as possible, and then the whole plant cluster is divided into several clusters, each with more roots, such as peony and peony. There are also some flowering shrubs and vines with strong sprouting ability, which often sprout many young clusters around the mother plant. When dividing the plants, it is not necessary to dig up the mother plant, only the tiller seedlings can be planted separately, such as rose, trumpet creeper, rose, etc.

(2) Potted flowers The division propagation of potted flowers is mostly used for grass flowers. Before division, remove the mother plant from the pot, shake off most of the soil, find the extension direction of each tiller root system, and separate the coiled roots to minimize the damage to the root system. Then use a knife to separate the root neck connecting the tiller seedling and the mother plant, and trim the root system, remove the old roots and diseased roots, and then immediately pot it. After watering, place it in the shade for maintenance. If wilting is found, spray water on the leaves and the surrounding area to increase the humidity. After the new buds sprout, turn to normal maintenance. Such as orchids, strelitzias, daylilies, etc.

(3) Cacti and succulent plants. Division is rarely used for cactus propagation. Only a few species such as white sandalwood, pine cypress, silver amber, and velvet ball can be used. These species are easy to produce baby balls, but the baby balls are not obviously different in size from the mother plant. The baby balls have already grown roots on the mother plant, thus forming a clump of plants. When they are too crowded, they need to be divided in time. The division is generally done by hand to separate the clumps into several clumps and plant them in pots separately. Division can be done all year round in the south, but spring is the best time. In the north, it is appropriate to do it in spring and summer. Division is more commonly used in succulent plants, such as aloe, tiger tail orchid, and Haworthia. There are often many small plants at the roots. These small plants will soon grow into the same shape as the mother plant and grow their own roots. They can be potted separately in the early growth period in conjunction with repotting.

In addition, some herbaceous plants often have modified stems such as runners, suckers, and bulbils in the rhizosphere or leaf axils. For example, some species of saxifrage, spider plants, strawberries, love lotus and lawn plants have runners, which can be picked off for cuttings; the suckers of aloe and pineapple can be cut off from the mother plant and planted separately; the bulbils of ground roots and Kalanchoe can be taken off and planted in the soil to take root and grow into a new plant.

2. Bulb division propagation

Most bulbous flowers have strong ability to divide underground, and they can grow some new bulbs every year. Using them to propagate is simple and can bloom early. The methods of dividing bulbs vary depending on the plant organs of the bulbs. There are mainly the following types:

(1) The bulbs of gladiolus and freesia are corms. Gladiolus and freesia have strong ability to divide. After flowering, when the old corms dry up, they can divide into several corms of different sizes. Large corms can bloom in the same year after being transplanted in the second year, while small corms need to be cultivated for 2-3 years before blooming. They can also divide into many small bulbs with a diameter of 0.5 cm. After these small bulbs are sown in rows, they can gradually grow into large bulbs (see Figure 5-1).

Figure 5-1 Ball division method (gladiolus)

(2) Bulbs Bulbs are modified underground stems with bulbous discs, which are covered with thick and fleshy scales and are spherical. Every year, several young bulbs are born from the stem disc at the base of the old bulb, which are clasped around the mother bulb. These young bulbs are separated and planted separately to cultivate large bulbs. Bulbs are divided into skin bulbs such as tulips, hyacinths, daffodils, and amaryllis, and skinless bulbs such as lilies and fritillaria, depending on whether they have a membranous outer skin (see Figure 5-2).

Figure 5-2 Bulbs (Daffodils)

(3) Tubers are modified stems formed by enlarged stems, which are nearly tuberous, with buds usually at the top of the tubers. For example, the underground part of canna has horizontal tubers with many branches, and the growth point is located at the top of the branches. When divided, each tuber branch must have a terminal bud in order to grow a new plant. New roots will develop at the nodes of the tuber. After this type of tuber is divided, it will bloom in the same year.

(4) Tuberous roots are formed by the enlargement and metamorphosis of underground roots. There are no buds on the tubers. Their buds are all on the rhizomes close to the surface. Simply planting a tuber will not produce a new plant. Therefore, when dividing, each part must have a root neck to form a new plant. Examples include dahlias and ranunculus (see Figure 5-3).

Dahlia tuber root

Figure 5-3 Root tubers (dahlia)

(5) Rhizome plants Some plants have thick and long root-like modified stems with nodes, internodes, buds and other structures similar to those of the aboveground stems. Roots can form on the nodes and send out lateral buds. After being cut off, they can become new plants. Examples include Calla Lily and Aspidistra.

(IV) Layering propagation

Layering propagation is mostly used for some woody flowers that are easy to root at the nodes and internodes, and some woody flowers that are not easy to root by cuttings. Layering is to ring and incise the branches that have not separated from the mother plant at the appropriate position, and can be combined with rooting promoters to apply treatment, and then bury the part in the soil. Since the injured part is easy to accumulate nutrients and hormones synthesized in the upper part, it is easy to form a root system. Then they are cut off from the mother plant and transplanted to another plant to form new seedlings. Layering propagation is a safe and reliable propagation method because the branch wood is still connected to the mother plant, it can continuously obtain water and mineral nutrients, and the branches will not dry up due to water loss. Its advantages are high survival rate, fast seedling formation, early flowering, and no special maintenance is required, but its disadvantages are that it occupies more land and has a small number of seedlings.

Layering can be done all year round in the south, with spring and rainy season being the most ideal. In the north, it is mostly done in spring or the first half of the year, so that there is enough time to form a complete root system before winter. Under the conditions of a medium or high temperature greenhouse, some flowers and trees can also be propagated by layering in winter. Layering methods can be divided into three types: ordinary layering, soil layering, and high branch layering.

1. Ordinary layering method

The single-branch layering method bends the longer branches at the bottom of the mother plant downward, then scars or peels the protruding parts of the downward bend in a ring shape, and then buries them in the soil, and fixes the downward bend parts with hooked branches or iron bars to prevent rebound. The tip of the pressed branch should be exposed to the soil surface and fixed with a bamboo pole to make it grow upright. The layered seedlings in spring are cut off from the mother plant in autumn. This method is mostly used for shrubs and small trees (see Figure 4-1-1).

The continuous layering method is to dig a longitudinal trench on one side of the mother plant, then cut the nodes of the branches close to the ground, and then bury them shallowly in the soil trench, with the tips of the branches exposed to the ground. After a period of time, the nodes buried in the soil can sprout new roots, and soon the axillary buds on the nodes will also sprout and push out of the soil surface. When the newly sprouted old plants mature, use branch shears to penetrate the soil to cut off the internodes of each section. After more than half a year of cultivation, they can be transplanted. This method is mostly used for shrubs and flowers (see Figure 4-1-2).

The wavy layering method is used for some climbing woody flowers, such as forsythia, grape, trumpet creeper, and ground ivy. Their branches are long and soft, especially the climbing species. Most of them can naturally produce new roots after the nodes are buried in the soil. They can be buried in the soil in a wave-like shape, node by node, without cutting. They will take root in about 20 days, and then the exposed internodes can be cut off one by one. The water and nutrients absorbed by the new roots at the nodes can be used for the germination of axillary buds, thus forming many seedlings (see Figure 4-1-3).

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Figure 4-1 Common layering methods

1. Single branch layering 2. Continuous layering 3. Wave layering 4. Soil layering

2. Soil layering method

Soil layering is also called pile layering. It is often used for some large deciduous or evergreen shrubs with strong clumping ability. Their branches have no obvious nodes, weak branching ability, and no fat and full axillary buds, such as purple magnolia, bauhinia, yellow thorn rose, pearl bush, gardenia, golden wood, etc. When layering, it is necessary to use the original branches to let their bases root, and a large number of seedlings can be obtained at one time. The method is to ring cut the lower part of the branches 20-30 cm from the ground during the peak growth season in early summer, and then pile up the soil to bury the lower half of the entire plant. The soil should be kept moist. After a certain period of time, new roots will grow from the wound after ring cutting. In the spring of the second year, the soil pile is dug up and cut off one by one from the bottom of the new roots, and it can be directly planted (see Figure 4-1-4).

2. High branch layering method

It is difficult for some evergreen woody flowers to root from cuttings. Tree species that cannot be pressed to the ground for layering due to reasons such as their branches being difficult to bend or not being long enough can be propagated by high pressure method. Such as orange, white orchid, Milan, jasmine, osmanthus, azalea, camellia, bergamot, etc. Use plastic film, half bamboo tubes, flower pots, etc. filled with nutrient soil or peat soil for wrapping. Perennial branches can be selected, preferably two-year-old branches, or semi-lignified branches of the current year can be selected, and the lower half of the branches can be wrapped in an appropriate part. If you use a flower pot to hold soil, you need to enlarge the drainage holes at the bottom of the pot in advance to facilitate the insertion of the flower pot from the top of the branch without damaging the leaves. No matter what material is used to hold the soil, the wrapped part should be ringed or scratched before wrapping to sprout new roots. The following are commonly used scratching methods:

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Figure 4-2 High branch layering method

1. Scratching 2. Flowerpot high pressure method 3. Thin film high pressure method

The scoring method is to carve several vertical scars on the pressed part, or to carve one or two circles horizontally, deep into the wood. This method is mostly used for flowers that are easy to root.

The peeling method is to carve off one or two tongue-shaped cortexes at the pressed part, taking off a small amount of wood. Some need to peel off a wider circle of phloem and scrape the cambium clean to prevent them from producing callus tissue to connect the severed phloem. It is even necessary to dry the wood at the wound and then wrap it with soil, so as to promote the formation of new roots in the cambium above the ring-barking. This method is mostly used for flowers that have difficulty in rooting.

The hanging method uses a thinner iron wire to tightly tie the buried part, so that it reaches deep into the xylem and cannot grow thicker, and cuts off the sieve tube of the phloem, so that the assimilated nutrients are concentrated here and stimulate rooting.

For some flowers that are relatively soft and easy to peel, the twisting method is used. When a large amount of high pressure is applied, in order to improve work efficiency, hands are often used to twist the pressed part to separate the phloem and wood.

When making wounds by the above method, growth hormone treatment can also be used in combination. Keep the soil moist after high pressure. The soil wrapped with plastic film is not easy to dry out. When adding water, you can untie the binding rope on it, or add water with a syringe. Most high-branch layerings need more than half a year of maintenance before being cut off from the mother body, and then potted with the original soil (see Figure 4-2).