What kind of culture soil is suitable for azaleas?

Soil selection is crucial to the growth and development of azaleas. There are many ways to prepare the soil for cultivating azaleas, which vary depending on the cultivar, but it must meet the following conditions: loose, smooth drainage, good ventilation, acidic soil, rich in humus, and sufficient base fertilizer. Rhododendrons usually grow vigorously only when they live in acidic loam soil. If they live in alkaline soil, their leaves will turn yellow and die soon. Rhododendrons are considered indicator plants for acidic soils. Humus soil is generally acidic soil, and pine leaf humus soil is the best and is an ideal culture soil for planting azaleas. You can dig under pine trees in mountainous areas, or go to courtyards where there are many pine and cypress trees. And add an appropriate amount of sulfur powder and alum before use to increase its acidity before use. Soil with high humus content is best for the growth of rhododendrons. There is a lot of humus, which can replenish the nutrients in the soil in time, improve the soil structure, and make the soil retain water, fertilizer, aeration, heat absorption and heat preservation. It can also reduce the harm of toxic substances in the soil and promote the expansion of the rhododendron's root system.

Black mountain mud, a new product from Tongguanshan in Yixing, Jiangsu and Fenghua, Zhejiang, is most suitable for the growth and development of azaleas and is widely used in various places. You can also make your own cultivation soil. Take 2 parts of weathered mountain topsoil, 1 part of fallen leaves, and 1 part of herbivore dried manure, mix them for one year, sift out impurities, and then use them. You can also use 3 parts of mountain soil, 3 parts of horse manure, 3 parts of fallen leaf weeds, and 1 part of human feces and urine to pile up in layers and sieve them after 1-2 years. The prepared culture soil should be stored indoors to prevent loss of fertility due to exposure to the sun and rain.

What should be paid attention to when repotting azaleas?

Azaleas should be repotted after cuttings survive. Mud pots with good transparency are the best flower pots, followed by purple sand pots, and glazed pots and porcelain pots are the worst. When potting, you should pay attention to the size of the flower pot, and avoid using large pots for small seedlings. If the pot is too large, the soil in the pot will not last long and the ventilation will be poor. At the same time, it will be difficult for the roots to reach the pot wall, which will affect the development of the seedlings. Generally, you can choose a mud pot with a diameter of about 10 cm for cutting seedlings, and then turn it into a flower pot with a diameter of about 15 cm after one year. When potting, you should pay attention to the drainage layer. First cover the drainage holes with tiles, then put in 1/3 of the coarse soil particles, and add a little fine soil. Then put the rhododendron seedlings in, hold the seedlings upright with one hand, and fill the pot with soil with the other hand. When filling the soil, be careful to only fill it to 2 centimeters below the mouth of the pot. Do not fill it too full to facilitate future watering. Finally, fill the pot around the pot and shake the pot to make the surface of the pot flat. After planting, water thoroughly with a watering can. Note that when boiling water, you must pour it until water seeps out from the bottom of the basin. If watering is not thorough and only the damp layer is scratched but not the inner layer, the potted flowers will dry out.

There are two situations in which azaleas need to be repotted. First, as the seedlings grow up and their roots fill the potting soil, they need to expand their root health. You should usually pay attention to whether there are roots protruding from the drainage holes at the bottom of the pot. If so, repot the plant and move the plant from a small pot to a large pot. Second, after potted flowers grow for 2-3 years, the pot soil is exhausted. In order to supplement nutrients and improve the soil, the pot soil must be replaced.

Repotting of rhododendrons is usually done after climbing or before budding in autumn. When repotting, remove part of the soil and use sharp shears to trim away the roots. Old roots are those roots that grow poorly and become black and shriveled. But be careful: when repotting the seedlings, do not trim the roots. When repotting the plant, attention should be paid to the soil ball at the root. After placing the pot, you should also pay attention to watering it thoroughly for the first time and allowing it to dry out in the next few days. If it is too wet, the root cuttings will rot. Generally, you have to wait until new roots grow before you can irrigate normally. If repotting in autumn, it is best to do it in October. Although azaleas like cold weather, they should be kept warm during the winter after repotting. If there is no greenhouse, you can set up a small shed in a sunny and ventilated place facing south and cover it with plastic film to survive the winter safely. Rhododendrons should be repotted once a year for small seedlings and once every 2-3 years for large azaleas.

How to water azaleas?

Watering azaleas is a very important task. Because the root system of azaleas is relatively weak, it is not tolerant to waterlogging and is not drought-tolerant. Too dry or too wet is detrimental to plant growth, so special attention must be paid to controlling the amount of water. If there is a lack of water during the leaf expansion period, the leaves of the azalea will turn yellow and curl. If they are too dry, they will die. If there is a lack of water during flowering, the petals will become soft and shriveled, the flowers will droop, the colors will not be bright, and the flowers will even wither and die. Therefore, watering must be done as appropriate according to the weather, whether it is sunny or rainy, the air is dry or humid, the moisture content of the pot soil, etc.

Watering time should be in the morning and evening, especially in hot summer, it is not advisable to water at noon. Because the roots are stimulated by cold water, the flowers will be damaged. The principle of watering is to water it until it is dry, water it thoroughly, and be careful not to water it half-way. Spring and autumn are the growth, flowering and bud-nurturing periods of rhododendrons, so more water is needed, but don't water too much during the flowering period, as excessive water will cause the flowers to wither early. Under normal circumstances, watering can be done every 2-3 days in spring and autumn. In summer, new branches sprout and grow vigorously, consuming a lot of water. In addition, the temperature is high and the air is dry, so it needs to be watered 1-2 times a day. If it hasn't rained for a few days and the air is dry, use a fine-eyed watering can to spray water on the flowers and leaves, and spray some on the ground around the flowerpot to increase the air humidity. In humid weather or rainy conditions, watering should be stopped and the accumulated water in the basin should be drained in time. Although the temperature drops after autumn, the air is dry and evaporation is still high. Watering should be done frequently to keep the pot soil moist. When the flower buds are differentiating, the amount of water should be appropriately controlled to promote the formation of flower buds.

After October, when the flower pot is moved indoors, the amount of watering should be reduced as appropriate. The water content in the branches is low and the plant tissue is fully developed, which can increase the cold resistance. At this time, just keep the pot soil slightly moist.

How to treat water quality when watering azaleas?

When watering azaleas, special attention should be paid to water quality. It is best to use natural rainwater as water, because natural rainwater does not contain bleaching powder and other chemicals and impurities. Next is river water and pond water, and then tap water. Tap water is purified soft water, which contains bleaching powder, liquid chlorine, alum and other chemicals. If this water is used for a long time, the alkalinity in the pot soil will gradually increase, which is not conducive to the growth of azaleas. Therefore, water quality must be treated before use. The treatment is to acidify it. For water that is neutral or alkaline, acidic water should be prepared. The usual method is to use ferrous sulfate (green vitriol) and vinegar to acidify the water. If the water quality is too alkaline, ferrous sulfate and vinegar can be used together. The specific dosage can be prepared according to the measured pH values ??of water, ferrous sulfate, and vinegar. The simple method is to add 0.1%-O in long-term watering. 5% ferrous sulfate aqueous solution, or sprinkle a little ferrous sulfate on the basin surface for 10-15 days. You can also pour an aqueous solution containing 0.5% to 1% vinegar once every 10-15 days. For watering, you can also use tap water and well water that have been dried. Drying water can reduce the harm of harmful ions in tap water; it can also increase the temperature of well water and eliminate the temperature difference between water and pot soil to facilitate root absorption. When using tap water, also add 0.15% ferrous sulfate. It would be more beneficial if watering can be done alternately with decomposed fertilizer liquid water. Because these two kinds of water are commonly used, the pot soil can maintain a certain acidity and supply certain nutrients, which is suitable for the growth needs of azaleas.

How should azaleas be fertilized?

Azaleas are a flower that does not require heavy fertilizer. If too much or too concentrated fertilizer is applied, it will be detrimental to its growth. But this does not mean that you should not fertilize. In order to make it bloom more and larger, you still need to apply some fertilizer at the right time and in the right amount. Therefore, flower gardening experts have summed up the experience of fertilization in 8 words: "Apply less dry fertilizer and less liquid fertilizer." This is very appropriate and worthy of reference by flower growers. Under normal circumstances, 1.2-year-old seedlings do not need to be fertilized because the fertility contained in the humus soil is enough to meet the needs of the seedlings' growth and development. For small plants that are 2-3 years old, dilute cake fertilizer or dilute alum fertilizer can be applied every 10 to 15 days starting from late spring or late summer. For plants over 4 years old, about 20 grams of dry cake fertilizer can be applied in spring and autumn each year. In mid-June, quick-acting phosphorus and potassium fertilizers can be applied once to promote flower bud differentiation. Fertilization can be stopped after June. After the flowers fade and new branches grow, you can apply a slightly higher concentration of liquid fertilizer once, but do not apply it too thickly, let alone raw fertilizer, otherwise it will damage the root system. Excessive fertilization in summer will cause old leaves to fall off and new leaves to turn yellow. It is particularly worth noting that the most common deviation for azaleas grown at home is not a lack of fertilizer on the plant, but damage caused by excessive fertilization. If the leaves become yellow due to excessive fertilizer, stop applying fertilizer immediately, dig out the dry fertilizer, and water more to wash away the accumulated fertilizer in the soil. After watering, move it to a ventilated place for maintenance. Needs to be rinsed 2 times. In this way, it can gradually grow normally after half a year.

If there are no abnormalities in the summer, the rhododendron will begin its second period of vigorous growth after the beginning of autumn. During this short period of time, dilute solutions of phosphate fertilizers such as superphosphate can be applied 1-2 times. , to supply the needs of plant growth and bud pregnancy. After each fertilization, water should be poured every 2 days, and the pot soil should be loosened once to allow the pot soil to fully aerate. After winter, as the weather gets colder and the plants stop growing, fertilization should also be stopped immediately. If you do not stop fertilizing to allow the plants to sprout young leaves, it will make it difficult for the rhododendron to survive the winter. Do not be careless.

How to prune and reshape azaleas?

Azaleas have strong germination and regeneration capabilities. Every 1-2 years, after the flowers fade, they need to be replaced with a new one that is smaller than the original one. Use a larger pot and replace it with new soil. Experienced flower growers often combine pruning and shaping when repotting, and consciously prune out a beautiful tree shape. When performing sulfur pruning, you should cut off dense branches, cross branches, weak branches, drooping branches, leggy branches, and diseased and insect-infested branches. This is not only for the beauty of the tree, but also to improve the conditions of ventilation and light transmission; to save nutrients , to make the main branches strong so that new shoots can germinate as soon as possible, so that when they bloom next year, they can achieve the purpose of more flowers, larger flowers, and bright colors.

After the rhododendron blooms, its remaining flowers often linger for a long time, which consumes a lot of nutrients. In order to prevent the nutrients from being consumed in vain, the remaining flowers should be picked in time to allow the nutrients to be supplied for the germination of new skills. In addition, the summer cuckoo, which has a shorter plant, has many horizontal branches. Every spring, many twigs will sprout from the roots of the branches. In order to centrally supply nutrients to the main branches and flowers, it will grow faster and If the gills are bigger, these small branches should be cut off in time. If there are too many flowers, in addition to retaining one branch per branch, the rest of the flowers should also be removed. Which tree shape is best for pruning can be decided according to your own preferences. There are umbrella-shaped, round, semi-circular, pagoda-shaped, square, etc. You can choose at will and then prune deliberately.

How to propagate rhododendrons by cuttings?

Rhododendrons can be propagated by five methods: cutting, grafting, layering, division and sowing. Among them, the cutting method is the most common. The largest amount; layering to form seedlings is the fastest, and grafting and propagation are the most complicated. Only varieties that are difficult to survive by cutting are grafted, and cultivated varieties are mainly used for sowing.

To propagate by cuttings, it is better to use a new shallow tile pot with a diameter of 20 cm, because it has good air permeability and is easy to take root. A culture soil mixed with 20% humus garden soil, 40% horse manure chips, and 40% river sand can be used as the substrate. The best time for cutting is in spring (May) and autumn (October), when the temperature is between 20-25℃, which is most suitable for cutting. When taking cuttings, use the semi-lignified and robust branch tips of the current year as cuttings, and use a very sharp knife to press them; cut out 6-10 cm of nodes, and the incisions must be smooth and neat. Cut off the lower leaves, leaving only 3-4 leaves at the top. Leaflet. Buy a vitamin B12 injection. After opening it, dip the cutting strips in the solution, take it out and let it dry for a while before cutting. Before inserting, you should use a watering can to spray the culture soil in the pot with moisture the day before, but do not spray too much. It will be moist enough by the next day, which is most suitable for cuttings. The depth of insertion is 3-4 cm. When inserting, first use chopsticks to make a hole in the soil, then insert the cuttings, compact them with your hands so that the pot soil is in full contact with the cuttings, and then water it thoroughly. After inserting, it is best to cover the flower pot with a plastic bag and tie the mouth of the bag with a tape. Open it when watering is needed, and tie it again after watering. The cut flower pots should be placed in a place without direct sunlight. The cut pot soil should be sprayed with water every day within 10 days. Except for rainy days, it can be sprayed once on cloudy days. It is advisable to spray twice in dry climates, but the amount of water sprayed every day is limited. Not too much. After 10 days, you still need to keep the soil moist. It should be shaded for 4-5 weeks, and then gradually allowed to receive some sunlight after germination. It usually takes about 2 months for roots to take root. After that, it only needs to be shaded for 2-3 hours at noon, and the rest of the time can be allowed to receive light to facilitate its own production of nutrients during photosynthesis.

How to propagate azaleas by layering?

Rhododendron layering propagation is also one of the commonly used propagation methods, and high-tech layering is generally used. Rhododendron layering is usually carried out between April and May. The specific operation method is: first take a strong branch that is 2-3 years old from the mother plant of the potted azalea, and use a sharp knife to cut a ring of branch bark about 1 cm wide at 10-12 cm from the top of the branch. The sieve tubes of the phloem are gently peeled off, cutting off the channels through which organic matter produced by the leaves is transported downwards, causing it to gather to accelerate cell division and form nodule-like protrusions to germinate root buds. Then wrap it twice loosely with a piece of rectangular plastic film, tie it tightly with a string 2-3 cm from the lower end of the circular incision, leave the upper end of the plastic film open like a trumpet bag, then fill it with moist soil and a little moss, and then Tie the upper port of the bag tightly, and move the flower pot to a place out of direct sunlight for daily management. When watering, spray water on the leaves, let the water flow down the branches, and slowly seep into the bag. Keep the soil in the bag constantly moist to facilitate the healing of wounds on the branches and enable them to sprout new roots as soon as possible. After about 3-4 months, when the roots grow to 2-3 cm long, the branches can be cut off, separated from the mother plant, and planted into new pot soil.

How to propagate rhododendrons by sowing seeds?

Sowing seeds is a sexual reproduction. Since the seed setting rate of natural hybridization is very low, artificial pollination is generally performed to increase the seed setting rate of rhododendrons and obtain more seeds. The main method is to select strong female plants with good growth and beautiful flowers when the azaleas are in full bloom, move them to the greenhouse, select 3-4 flowers with large flowers and early blooms in each pot, and remove the stamens and new buds near the flowers. Concentrate the nutrients, and when mucus appears on the stigma head, use a new brush to dip the male parent's pollen into it and apply it a few times. One week after pollination, move the flowerpot outdoors and strengthen water and fertilizer management. After about 5-6 months of growth and development, by 11 to 12 months you will see the fruit gradually change from green to brown, and the seeds will mature. Pluck it immediately, let it dry in the shade, lift it clean, and place it in a cool and ventilated place.

Rhododendron seeds are very small and should not be stored for a long time, otherwise the germination rate will be low. If they are evergreen rhododendron seeds, they should be sown as they are picked and sown in pots in the greenhouse; if they are deciduous rhododendron seeds, they can be sown next spring.

The sowing pot should be a shallow tiled pot. For sowing soil, you can dig loose topsoil with moss on the surface of a sunny hillside and remove the stones. It is best to use 40% formalin. Add 100 times the diluent of water and spray once to disinfect, then dry. You can also put it in steam for 15-25 minutes to sterilize, and then dry it in the sun until it is half dry. Before sowing, first water the shallow pot with moisture, put a layer of about 2 cm of charcoal chips in the bottom layer, then spread a layer of 5-6 cm thick sterilized soil, scrape it flat, compact it slightly, and then divide the seeds evenly. Put the grid on it and press it gently. Do not use a watering can to spray water. It is best to use the method of soaking in a basin and sitting in water. Cover it with a piece of glass and move it to the greenhouse. When the surface of the pot soil is dry, you can spray some water in the form of mist, but do not spray too much. Just keep the pot soil moist.

After sowing, it usually takes 5-6 weeks to germinate. When the seedlings grow 2-3 true leaves, you can use small bamboo slices to gently pinch them out and plant them in separate pots. Do not plant them too densely, but sparsely. After planting, use reed mats to shade them, and do not allow them to be allowed to grow. Keep it out of direct sunlight and out of rain.

Do not apply fertilizer when the seedlings are young. Wait until the seedlings grow to nearly 10 centimeters in height in the second year before starting to apply thin fertilizer. Generally, individual plants can be planted separately from late spring to early autumn in the second year. In the third year, when the seedlings grow to 20 centimeters tall, a few seedlings can produce flowers if they are well maintained.

What are the common diseases of azaleas? How to prevent and control them?

The main diseases of azaleas include root rot, brown spot, black spot, leaf blight, and iron deficiency yellow. Diseases, etc.

After azaleas suffer from root disease, their growth will be weak, their leaves will be wilted and dry, water-soaked brown patches will appear on the surface of the root system, severe soft rot will occur, and the xylem will gradually rot and peel, and the xylem will turn black. This disease is most likely to occur in environments with high temperature and humidity.

The prevention and control method is to strictly disinfect the soil before repotting, and keep the soil loose and moist, so that it has good permeability and avoid water accumulation. If a plant is found to be diseased, the diseased plant and pot soil must be dealt with promptly. During treatment, 0.1% potassium permanganate aqueous solution or 2% ferrous sulfate can be used to rinse the diseased plants, then rinse with water and then repot. It can be cured by spraying the potting soil with a solution of 70% thiophanate wettable powder and 1000 times water.

Brown spot is a major disease of rhododendrons. When the disease first occurs, small brown spots appear on the leaves, which gradually develop into large irregular spots. Many black or gray-brown spots appear on the spots, causing the affected leaves to turn yellow and fall off, affecting the flowering of the current year and the development of flower buds in the next year. . This disease often occurs during the rainy season when the humidity is high.

The treatment method is to pay attention to allowing the plants to be ventilated and light, to prevent the humidity from being too high, and to apply more organic fertilizers and nitrogen, phosphorus and potassium mixed fertilizers to enhance the plants' ability to resist infection and grow. If diseased leaves are found, remove them immediately and burn them intensively. In the early stage of the disease, spray 0.5% Bordeaux liquid or 0.4 Baume lime sulfur mixture, and add 4% flour to increase adhesion. Leaf spot and black spot can also be treated in the same way.

Iron deficiency yellowing disease often occurs in areas with alkaline soil. When the disease is mild, only late greening of the plants appears; when severe, the leaf tissue may all turn yellow and the edges of the leaves become scorched. When the disease occurs, it is most obvious on the leaves at the top of the plant, and is generally caused by internal iron deficiency.

The prevention and control method is to change the properties of iron deficiency in the soil and reduce soil alkalinity. Apply more organic fertilizer to improve clay soil. Iron-deficient plants can be sprayed directly with O. 2% to 0.3% ferrous sulfate solution. You can also use chopsticks to poke several holes about 15 centimeters deep in the soil around the plant, and slowly inject 1:30 ferrous sulfate aqueous solution to fill the holes to increase soil acidity and reduce alkalinity.

The incidence and environmental conditions of cuckoo black spot disease are similar to those of brown spot disease, and similar methods can be used for prevention and treatment.

What are the common pests of azaleas? How to prevent and control them?

Common pests of azaleas include: red spider mites, armyworms, aphids, short-bearded snails, etc. Spider mites are tiny in size but can cause serious damage to rhododendrons. Rhododendrons growing in high-rise buildings are most susceptible to this type of pest infestation.

The prevention and control method is artificial hunting. To kill insects, you can use 5-degree lime sulfur mixture. You can also crush walnut leaves, yangzhu peach leaves, and green bamboo leaves in equal parts and soak them to extract the juice. Add water to dilute them and then sprinkle them. Spray them with 1,000 liters of dichlorvos liquid. It's also a good idea.

The adult armyworm is small and flat, about 4 mm long, and black. It is the most serious pest that harms evergreen rhododendrons. It often sucks leaf sap from the back of the leaves and damages the leaves. Yellow and white spots appear on the surface, causing the leaves to fall off, weakening the tree, and affecting growth and flowering. Rhododendrons in greenhouses are very susceptible to this insect.

The main method of prevention and control is spraying with drugs. It can be controlled by spraying 90% trichlorfon original drug 1000 times solution or 40% omethoate EC 1500 times solution or 50% fenitrothion emulsion 1000-1500 times solution.

Aphids mainly damage the young branches and leaves of azaleas. In mild cases, the leaves will lose their green color. In severe cases, the leaves will curl up, become hard and brittle, and cannot absorb nutrients, affecting flowering.

The control method is to pay special attention to aphids in the overwintering period. After winter, you can spray a 5-degree lime sulfur mixture on the plants to eliminate overwintering eggs, shovel weeds near flowers, and eliminate the source of insects. . During the aphid damage period, use 40% dimethoate or omethoate plus 1,200 times water to make a solution for continuous spraying. The effect can be seen after 3-4 times.

The short-bearded cuckoo is one of the important pests of rhododendrons. It often sucks sap near the main vein on the back of the leaves, causing many oil-stained patches on the back of the leaves, and finally causes the leaves to fall off. This insect has an obovate shape, a body length of about 0.3 mm, a flat body, and a body color ranging from red, dark red, or woody red. There are irregular black spots on the back of the body and irregular black patches on the sides of the body. This insect is most common in summer when the weather is hot and dry, and then decreases when rainfall is high.

The control method is to spray Baume 0.5 degree lime sulfur mixture once in mid-to-late October and in early spring in March. The effect of spraying 500 times of 25% insecticidal water swelling agent is also good.