Cutting methods of Rhododendron

In the cutting method of rhododendron, cutting method is often used to propagate rhododendron. Rhododendron cuttings can be carried out from April to August, and the matrix is better with sediment in the gully, or can be replaced by river sand. After screening, 1% potassium permanganate is used for sterilization and placed in a tile basin for use. Break the new semi-lignified branches by hand, and remove the lower leaves as cuttings, which can not be cut, otherwise the effect is not good.

It should be noted that if the new base is horseshoe-shaped, with extra epidermis, it will be cut off. When cutting, make a good hole on the substrate with a stick of suitable thickness, and then insert the cuttings into about half of the cuttings and water them with a fine spray pot so that the cuttings are in close contact with the substrate.

Cover the tile basin with plastic film, put it in a cool and ventilated place, avoid the sun, so as not to kill the cuttings. The number of water sprays depends on the weather and can take root in about a month. Gradually prolong the sun time after rooting, but should avoid exposure, about 3 months can be divided into pots, with this method of cutting survival rate can reach 100%, the above is the introduction of rhododendron cutting methods.

Culture methods of rhododendron

Rhododendron is the flower of Taifu in China. Among all the flower admirers, it can be called flowers, leaves and beauty, and it is suitable to plant in the ground and potted, and the azaleas are the most commonly used.

Azaleas-to everyone's favorite flowers and plants, presumably many people have raised azaleas, then many people may not be very clear about the cultivation of rhododendrons. Today, I would like to introduce the relevant skills and ways of cultivating rhododendrons. I hope it can help you when you cultivate azaleas.

Here's how to raise azaleas.

How to raise azaleas well? The most important thing is to understand the premise of its development. Azaleas have "six joys" and "six taboos".

① likes the wind and cool, but avoids summer heat.

② likes half shade and avoids the scorching sun.

③ prefers dampness to dryness

④ prefers acidic soil to alkaline soil.

⑤ prefers light soil to clayey soil.

⑥ likes excellent drainage and avoids waterlogging.

After coming out of the room in spring, the sun is softer, and the azaleas should be properly shaded around noon.

After the beginning of summer, the azaleas should be put in a cool and ventilated place. in hot summer, Reed curtains, bamboo curtains and sunshade nets should be used to shade, and the curtains should be opened before 8: 00 in the morning and 5: 00 to 6: 00 in the afternoon. Because the cuckoo is a semi-negative flower, the young leaves are easy to burn in the scorching sun. If the summer is exposed to strong light for a long time, it will cause branches and leaves withered and yellow, obstacles to development, and in serious cases, the whole plant will perish.

The sun intensity slows down gradually in autumn, and the azaleas can see more sunshine before 9: 00 in the morning and 5: 00 in the afternoon, and put in a sunny place at the end of autumn to promote flower bud differentiation. The cuckoo is not hardy, so it should be moved indoors between Cold Dew and Frosts Descent and placed in a sunny place. In the early stage of entering the room, attention should be paid to opening the windows and doors for ventilation. If you keep it in the shade for a long time, it is easy to drop buds. Culture methods of Rhododendron in Rhododendron Culture

The cultivation method of azaleas and how to cultivate beautiful azaleas.

Brief introduction of Azalea

One of the top ten famous flowers in China. Among all the ornamental flowers and trees, it can be called flowers, leaves and beauty, suitable for both ground and potted plants, and the most widely used. Bai Juyi praised and said, "if you take a closer look at the two branches in your hand, it doesn't seem to be in the human world. This thing in the flower is Xi Shi, and the whip Rong peony is the mother." In the natural distribution of azaleas in the world, there are so many species and huge quantities that none of them can compete with Chinese azaleas. China is the treasure house of rhododendron resources in the world! Today, in Jiangxi, Anhui and Guizhou, rhododendron is the provincial flower, and as many as seven or eight cities are designated as city flowers.

It is one of the top ten famous flowers in China. Rhododendron can be said to have beautiful flowers, beautiful leaves and a wide range of uses. As one of the most famous flowers in the world, it is a small shrub in the rhododendron family, with evergreen and deciduous leaves. Rhododendrons are distributed all over the temperate zone of the northern hemisphere. Among the more than 900 varieties in the world, there are nearly 600 in China, so the rhododendron has been selected by some enthusiasts as one of the candidate national flowers in China. The colorful azaleas evoke people's warm and beautiful feelings for life, and it also symbolizes the prosperity of the country and the happy life of the people. This is the true meaning of our people's love for cuckoos. Therefore, rhododendron has become the city flower of many cities in China, and it is also the national flower of many countries. It is very beautiful, tubular flowers, with crimson, light red, rose, purple, white and other colors. When the azaleas bloom in spring, the mountains are bright, like rosy clouds around the forest, worthy of the "beauty in the flowers".

2. It has many classifications. Most varieties have low plants and natural shape, while a few varieties are tall and majestic with whirling branches and leaves. Low varieties have many branches, thin and dense branches, young branches hairy, brown or brown. Flowers solitary or in racemes, Corolla campanulate, tubular or broadly funnelform, usually 5-lobed. There are many colors, depending on the variety, there are lilac, sprinkle gold, some have two colors, some flowers have aroma. The capsule is dark brown when mature, and the seeds are dark yellow and fine. According to the different florescence, it can be divided into four categories: spring cuckoo, summer cuckoo, spring and summer cuckoo and western rhododendron.

3. Its living environment. Cuckoos like semi-shady environment, avoid direct exposure to the scorching sun, like cold and humid climate, afraid of hot and dry weather, like acidic soil and water, avoid alkalinity, like loose light loam rich in humus, afraid of clay soil with poor drainage, like light fertilizer water, and avoid applying thick fertilizer water. It has certain requirements for light, but it is not resistant to exposure. There should be deciduous trees or shade in summer and autumn to cover the scorching sun, and the ground is often sprayed with water. Rhododendron shoots are usually in spring and autumn, mainly spring shoots. The most suitable temperature for growth is 15-20 ℃. When the temperature is over 30 ℃ or below 5 ℃, the growth is stagnant. At the same time, it is also resistant to pruning, and hidden buds are easy to germinate after stimulation, which can be used to control the shape of the tree and rejuvenate the tree.

What kind of soil is rhododendron suitable for?

The choice of soil is very important for the growth and development of rhododendron. There are many methods for the cultivation of rhododendron, which vary from variety to variety, but they must have the following conditions: loose, unobstructed drainage, good ventilation, acidic soil, rich humus and sufficient base fertilizer. Usually azaleas thrive when living in acidic loam. If they are in alkaline soil, they soon die of leaf yellow exhaustion. Rhododendron is regarded as an indicator of acidic soil. Generally speaking, rotten leaf soil belongs to acid soil, and pine leaf humus soil is the best, which is an ideal culture soil for planting rhododendron. You can dig under the pine and cypress forest in the mountain area, or you can take soil under the ground where there are many pine and cypress trees in the courtyard. And add appropriate amount of sulfur powder and alum before use to improve its acidity before use. The soil with high humus content is the most suitable for the growth of rhododendron. There is a lot of humus, which can replenish the nutrients in the soil in time, improve the soil structure, preserve soil water, keep fertilizer, aerate, absorb heat and keep heat. It can also reduce the harm of toxic substances in the soil and promote the root system of rhododendron to expand in all directions.

Tongguanshan in Yixing, Jiangsu Province and Montenegro mud, a new product in Fenghua, Zhejiang Province, are most suitable for the growth and development of rhododendron. The cultivated soil can also be self-made. Take 2 parts of weathered mountain topsoil, 1 part of deciduous leaves, 1 part of dry dung of herbivores, mix for 1 year, sift out impurities, and then use. It can also be piled up with 3 parts of mountain skin soil, 3 parts of horse dung, 3 parts of deciduous weeds and 1 part of human feces and urine, which can be screened and used after 1-2 years. The prepared culture soil should be stored indoors to prevent fertility loss due to sun and rain.

What should be paid attention to when turning the azaleas into pots?

Azalea cuttings should be put on the pot if they survive. In flowerpots, mud pots with good permeability are the best, purple sand pots are the second, and glaze pots and porcelain pots are the worst. When going up the pot, you should pay attention to the size of the flowerpot and avoid small seedlings with large pots. If the basin is too large and the basin soil does not exist for a long time, the ventilation will be bad, and the root system is not easy to reach the basin wall, affecting the development of seedlings. General cuttings can choose a mud pot with a diameter of about 10 centimeters, and then turn into a flowerpot on the left side of 15 centimeters a year later. When going up the basin, you should pay attention to do a good job of the drainage layer, first cover the drainage hole with tiles, and then put in the coarse soil particles of 1 big 3, and add a little fine soil. Then put the cuckoo seedlings in, straighten the seedlings with one hand, and fill the pot with the other. Fill can only be filled to 2 cm below the mouth of the basin, not too full, so that it can be watered in the future. Finally, fill the pot around and shake the flowerpot to make the basin flat. After planting, use a spray can to water it once. Note that when boiling water, it must be poured until the bottom of the basin has water seeping out. If the watering is impenetrable, only scratch the decaying layer but not the inner layer, it will dry the potted flowers to death.

There are two situations in which azaleas need to be turned over. First, the seedlings grow up and the roots are full of potted soil, so it is necessary to expand the extension range of Genkang. At ordinary times, you should pay attention to whether there is a root protruding from the drainage hole at the bottom of the basin, and turn the plant into the big basin from the small basin. Second, after the potted flowers grow for 2-3 years, the bloated content of the potted soil is exhausted. In order to supplement nutrients and improve the soil, it is necessary to replace the potted soil.

The turning of azaleas is usually carried out after climbing flowers or before budding in autumn. When turning the basin, remove part of the lodging soil and pay attention to trimming the root with a sharp cut. Old roots are those that grow poorly and are blackened and shriveled. But it should be noted that when the seedlings are turned over, the roots can not be trimmed. When turning the pot, you should pay attention to the root with a soil ball. After putting on the basin, you should also pay attention to the first watering and let it dry in the next few days. If it is too wet, the root cut will rot. Usually it can not be irrigated normally until the new root grows. If you turn the pot in autumn, it is best to do it in October. Although azaleas like to be cold and cool, they should pay attention to heat preservation after turning the pot for the winter. If there is no greenhouse, you can build a shed in the south-facing sun-ventilated place and cover it with plastic film to make it through the winter safely. Rhododendron pot, generally small seedlings turn once a year, big rhododendrons turn the pot once in 2-3 years.

How to water the azaleas?

Watering azaleas is a very important task. Because the root system of rhododendron is relatively weak, both waterlogging and drought tolerance, too dry or too wet are disadvantageous to plant growth, so special attention should be paid to water control. If there is a lack of water during the leaf expansion period, the leaves of the azaleas will turn yellow and curl. If they dry badly, they will die. If there is a lack of water when blooming, the petals will be soft and shrivelled, the flowers will droop, the colors will not be bright, and even the flowers will wither and die. Therefore, it must be watered according to the weather, dry and wet air, water content of basin soil and so on.

Watering time should be in the morning and evening, especially in the hot summer is not suitable for watering at noon. Because the roots are stimulated by cold water, the flowers will be hurt. Watering principle is not dry do not water, watering must be thoroughly, strictly prevent half of the water. Spring and autumn are the growth, flowering and budding periods of azaleas. The water supply should be more appropriate, but the flowering period should not be watered too much. Water will make the flowers wither as soon as possible. In general, spring and autumn can be watered every 2-3 days. New shoots sprout in summer, grow vigorously, consume a lot of water, coupled with high temperature and dry air, need 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-eye spray can to spray water on the flowers and leaves, and spray some on the ground around the flowerpot to increase the air humidity. In the case of Huangmei or rainy days, stop watering and drain the stagnant water from the basin in time. Although the temperature decreases after autumn, the air is dry and the evaporation is still very large, and the basin soil should be often watered to keep the soil moist. During flower bud differentiation, the amount of water should be properly controlled to promote the formation of flower buds. After October, the flowerpot enters the room, the amount of water should be reduced as appropriate, the water content in the branches is less, and the plant tissue is well developed, which can increase the ability of cold resistance. At this time, keep the basin soil a little wet.

How to treat the water quality when watering azaleas?

When watering azaleas, you should pay special attention to the water quality. It is best to use natural Rain Water for water, because natural Rain Water does not contain drugs and impurities such as bleach. The second is river water and pond water, and the third is tap water. Tap water is purified soft water, which contains bleaching powder, liquid chlorine, alum and other chemicals. If this kind of water is used for a long time, it will gradually increase the alkalinity in the basin soil, which is not conducive to the growth of azaleas. Therefore, the water quality must be treated before use. The treatment is to acidify it. Water with neutral or alkaline water quality should be prepared into acidic water. The usual method is to acidify water with ferrous sulfate (green alum) and edible vinegar. If the water quality is too alkaline, ferrous sulfate and edible vinegar can be used together, and the specific dosage can be prepared according to the pH value of water, ferrous sulfate and vinegar. The simple method is to irrigate an aqueous solution containing 0.1%-0.5% ferrous sulfate for a long time, or sprinkle a little ferrous sulfate on the basin surface for 10-15 days. An aqueous solution containing 0.5%-1% vinegar can also be irrigated once in 10-15 days. Watering can also use tap water and well water after drying treatment. Drying water can reduce the harm of harmful ions in tap water, increase the water temperature of well water, eliminate the temperature difference between water and basin soil, and facilitate root absorption. 0.15% ferrous sulfate is also added when using tap water. When watering, it is more beneficial if it can be irrigated alternately with mature fertilizer liquid water. Because the common use of these two kinds of water can not only maintain a certain acidity of the basin soil, but also provide certain nutrients, which is suitable for the growth of azaleas.

How should azaleas be fertilized?

Rhododendron is a kind of flower that does not need big fertilizer. If the fertilizer is applied too much or too thick, it will be harmful to its growth. But this does not mean that it should not be fertilized, but that it should bloom more and more, and that the sky should apply some fertilizer at the right time and in the right amount. Therefore, flower growers summed up eight words of experience in fertilization: "less dry fertilizer, less liquid fertilizer". This is very appropriate and worthy of reference by florists. In general, 1. 2-year-old seedlings do not need to apply fertilizer, because the fertility contained in humus soil is enough to meet the needs of seedling growth and development. For 2-3-year-old plantlets, thin cake fertilizer or thin alum fertilizer and water can be applied every 10-15 days from late spring or tough summer. Plants more than 4 years old can apply about 20 grams of biscuit fertilizer in spring and autumn each year. In the middle of June, available phosphorus and potassium fertilizer can be applied once to promote flower bud differentiation. Fertilization can be stopped after June. After the flower fade, it is the time for the new branch to grow, you can apply a slightly higher concentration of liquid fertilizer, but must not be too thick, do not apply raw fertilizer, otherwise it will damage the root system. Excessive fertilization in summer will make the old leaves fall off and the new ones turn yellow. It is particularly noteworthy that the deviation of azaleas planted at home is not due to lack of fertilizer, but to the damage caused by excessive fertilization. If the leaves are withered and yellow due to excessive fertilizer, the application of fertilizer should be stopped immediately, dry fertilizer should be removed, and more water should be watered to remove the fertilizer in the remaining soil, and some should be washed twice after pouring. In this way, it can grow normally gradually after half a year.

If there is no anomaly in summer, the cuckoo will begin the second period of vigorous growth after the Beginning of Autumn. In this short period of time, the dilute solution of phosphate fertilizer such as calcium superphosphate can be applied 1-2 times to meet the needs of plant growth and bud pregnancy. After each fertilization, fresh water should be irrigated every 2 days, and the basin soil should be planed loose once to make the basin soil fully ventilated. After the beginning of winter, as the weather gets colder and the plants stop growing, fertilization should stop immediately. If you do not stop fertilizing, make the plant sprout tender leaves, but will make it difficult for cuckoos to survive the winter, do not be careless.

How to prune azaleas?

Rhododendron has a strong ability to germinate and regenerate. After the flower fades every 1-2 years, it is necessary to change a larger flowerpot and replace it with new culture soil. Experienced flower growers often combine pruning and shaping at the same time when changing pots to consciously prune a beautiful tree. When carrying out sulfur shearing, dense branches, cross branches, slender branches, drooping branches, overgrown branches and disease and insect branches should be cut off, which is not only for the beauty of the tree type, but also to improve the conditions of ventilation and light transmission, and to save nutrients and make the main branches strong. In order to sprout new shoots as soon as possible, so that the coming year can achieve the purpose of more flowers, large flowers and colorful flowers.

After the cuckoo blossoms, its residual flowers often last for a long time, which consumes a lot of nutrients. In order not to let nutrients be consumed in vain, the residual flowers should be picked in time to supply nutrients to sprout new technologies. In addition, the shorter summer cuckoo has many transverse branches. every spring plum, many twigs sprout from the roots. In order to concentrate nutrients on the main branches and flowers, so that they can grow faster and have bigger gills, these twigs should also be cut off in time. If there are too many flowers, in addition to keeping each branch for a long time, the rest of the flowers should also be removed. You can decide which tree shape to trim according to your own preferences, such as umbrella shape, circle, semicircle, pagoda, square, etc., and then deliberately trim it.

How do azaleas propagate by cuttings?

The cuckoo can be propagated by cutting, grafting, striping, splitting and sowing, among which the cutting method is the most common and the reproduction quantity is the largest; the seedling formation by pressing is the fastest and the grafting propagation is the most complex. Only varieties that are not easy to survive by cutting are grafted, and sowing is mainly used to cultivate varieties.

The use of cutting propagation, cutting pot to 20 cm diameter of the new shallow tile basin is better, because of its good air permeability, easy to take root. The culture soil composed of 20% humus garden soil, 40% horse dung dust 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 and 25 ℃, which is the most suitable for cutting. when cutting, select the semi-lignified and sturdy branches of the same year as cuttings, press the knife with extremely tweezers; cut 6-10 cm with nodes, cut off the lower leaves, leaving only the top 3-4 leaflets. Buy a vitamin B12 injection, open it, dip the cuttings in the liquid, take it out and dry it for a while. Before cutting, you should spray the soil in the basin with a spray can the day before, but do not spray too much. It is mocking and moist the next day, which is most suitable for cutting. The depth of the insert is 3-4 cm. When inserting, first use chopsticks to save a hole in the soil, and then insert the cuttings, compacting them with their hands, so that the potted soil is in full contact with the cuttings, and then pour water once. After inserting, the flowerpot had better be covered with a plastic bag, the mouth of the bag is tied with a belt, open when it needs to be watered, and then re-fastened after pouring. The cutting flowerpot should be placed in a sunless place, and the cutting pot soil should be sprayed with water every day for 10 days. Except for rainy days, it can be sprayed once in cloudy days and twice in dry weather, but the amount of water sprayed every day should not be too much. LO days later, always pay attention to keep the soil moist. It should be shaded for 4-5 weeks, and only after budding can it be gradually allowed to accept some sunlight. It usually takes about 2 months to take root. After that, it only needs to shade for 2-3 hours at noon, and allow it to receive light the rest of the time, in order to make its own nutrients in its photosynthesis.

How do azaleas reproduce with strips?

Rhododendron striping propagation is also one of the commonly used breeding methods, generally using high-tech striping. Rhododendron embossing is usually carried out between April and May. The specific operation method is as follows: first, take 2-3-year-old robust branches from the mother plant of potted azaleas, cut open a ring of annular branches about 1 cm wide with a sharp knife 10-12 cm away from the top of the branches, gently peel off the sieve tube of the phloem, cut off the channels for the downward transport of organic matter from leaves, and make them gather, so as to accelerate cell division and form nodular protuberances and germinate root buds. Then wrap two loops loosely with a piece of rectangular plastic film, fasten it with a string at the lower end of the circular incision 2-3 cm, leave the upper end of the plastic film open into a trumpet bag, then fill in the wet soil and a little moss, tie up the upper end of the bag, and move the flowerpot out of direct sunlight for daily management. When watering, you should spray water on the leaves, let the water flow down the branches and slowly seep into the bag to keep the soil in the bag often moist, so as to facilitate the wound healing on the branches and sprout new roots as soon as possible. About 3-4 months later, when the roots grow to 2-3 cm long, the branches can be cut off, leaving the mother plant and planted in a new pot soil.

How do azaleas sow and reproduce?

Sowing is sexual reproduction. As the seed setting rate of natural hybridization is very low, artificial pollination is generally needed to improve the seed setting rate of rhododendron and obtain more seeds. Its main method is when the azaleas are in full bloom, choose strong female parents with good growth and beautiful colors, move to the greenhouse, leave 3-4 flowers with large flowers and early flowering in each pot, pick the stamens and new buds near the flowers, and concentrate nutrients. When mucus appears on the head of the style, just use a new brush to dip the pollen of the male parent and apply it for a few times. A week after pollination, the flowerpot was moved outdoors to strengthen the management of water and fertilizer. After about 5-6 months of growth and development, the fruit gradually changed from cyan to brown and the seeds matured in 11-12 months. Immediately pick it, let it dry, clean, and put 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 is low. If evergreen cuckoo seeds should be sown with picking and sowing in pots in the greenhouse, deciduous rhododendron seeds can be sown until next spring.

The sowing basin should be a shallow tile basin, sowing soil, you can dig the loose topsoil with moss on the surface of the sunny hillside, pick up the stone grains, spray it with 40% formalin and 100 times water diluent, disinfect it, and then dry it. It can also be steamed in steam for 15-25 minutes for disinfection, then bask in the sun until half dry and ready for use. Before sowing, first pour the tide in the shallow basin, put a layer of charcoal shavings of about 2 centimeters at the bottom, and then spread a layer of sterilized soil 5-6 centimeters thick, scrape flat, slightly compact, and then evenly divide the seeds above, gently press them, and do not spray water with a spray pot. It is best to use the method of soaking the basin and sitting on water. Cover it with a piece of glass and move it to the greenhouse. When the surface of the basin soil is dry, you can spray some water foggy, but do not spray too much, always keep the basin soil moist.

After sowing, it can germinate after 5-6 weeks. When the seedlings grow out of 2-3 true leaves, they can be gently sandwiched out with small bamboo slices and planted in another pot. Do not plant too densely, but sparsely. After planting, use Reed mats and other shade. Do not let the sun shine directly or let Rain Water get drenched. When the seedlings are young and tender, do not apply fertilizer, wait until the next year when the seedlings grow to nearly 10 cm high, and then begin to apply thin fertilizer; generally, from the end of the second spring to early autumn, individual plants can be planted separately. By the third year, when the seedlings grow to 20 cm high, if they sprout well, a few seedlings will be able to produce flowers.

What are the common diseases of rhododendron? How to prevent and cure?

The main diseases of rhododendron are root rot, brown spot, black spot, leaf blight, iron deficiency chlorosis and so on.

After the rhododendron suffered from root arm disease, the growth was weak, the leaves wilted and withered, the surface of the root system appeared water-stained brown fields, serious soft rot, gradually rotted and peeled, and the xylem blackened. The disease is most likely to occur in an environment with high temperature and high humidity.

The prevention and control method is to strictly disinfect Pei 10 soil before turning the basin, and keep the soil condition sulfur loose, moist, make it have good permeability, and avoid stagnant water. If the plant is found to be sick, the diseased plant and basin soil should be dealt with in time. During treatment, the diseased plant can be eluted with 0.1% potassium permanganate aqueous solution or 2% ferrous sulfate, then rinsed with clean water and put on the basin again. The basin soil can be cured by spraying basin soil with a solution of 70% topzine wettable powder and 1000 times water.

Brown spot is a major disease of rhododendron. At the beginning of the disease, small brown spots appeared on the leaf surface, which gradually developed into irregular spots, and many black or grayish brown spots were produced on the disease spots, which made the damaged leaves yellow and fall off, affecting the flowering of the current year and the development of flower buds in the coming year. This disease often occurs during the rainy season when the humidity is high.

The treatment method is to pay attention to make the plant ventilated and transparent, not to make the humidity too high, and to increase the application of organic fertilizer and nitrogen, phosphorus and potassium mixed fertilizer to enhance the plant resistance to infection and growth. If diseased leaves are found, they should be removed in time and burned centrally. At the initial stage of the disease, 0.5% Bordeaux solution or 0.4 Baume stone sulfur agent was sprayed, and 4% flour was added to increase the adhesion. Leaf spot and black spot can also be treated with the same method.

Iron deficiency chlorosis often occurs in alkaline soil areas, when the disease is mild, only the plant late green phenomenon; in severe cases, the leaf tissue can all turn yellow and the leaf edge scorched. When the disease occurs, it is most obvious in the leaves of the top tip of the plant, which is generally caused by internal iron deficiency.

The control method is to change the property of iron deficiency in soil and reduce soil alkalinity. Apply more organic fertilizer to transform clayey soil. 0.2%-0.3% ferrous sulfate liquid can be directly sprayed on iron-deficient plants. You can also poke several holes about 15 cm deep in the soil around the plant with chopsticks and slowly inject them with liquid ferrous sulfate solution at 1:30 to fill the holes to increase soil acidity and reduce alkalinity.

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

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

Common pests of azaleas are red spiders, military insects, aphids, short beard cochlea and so on. Red spiders are small in size, but they do serious harm to azaleas. Cuckoos raised in high-rise buildings are most prone to this kind of pest.

The method of prevention and control is to hunt and kill manually. Medicine can be used to kill insects with 5 degrees of stone sulfur mixture, or you can use walnut leaves, Yangzhu peach leaves, green poles and other parts to soak out the juice, dilute it with water and sprinkle it with ll, and it is also a good way to spray and kill with 1000 dichlorvos solution.

The adult body of the military worm is small and flat, about 4 mm long and black. It is the most serious pest to the evergreen rhododendron. It often sucks leaf juice behind the leaves, and yellow and white spots appear on the leaves of the injured area, causing the leaves to fall off, causing the tree to weaken and affecting growth and flowering. This insect is easy to occur in rhododendrons in greenhouses.

The main method of prevention and treatment is to spray and kill with medicine. It can be sprayed with 1000 times of 90% trichlorfon or 1500 times of 40% omethoate EC or 1000-1500 times of fenitrothion emulsion.

Aphids mainly harm the young branches and leaves of rhododendron, light ones can make the leaves lose green, heavy ones make the leaves curl, become hard and brittle, can not absorb nutrients and affect flowering.

The control method is to pay special attention to the aphids during the overwintering period. after wintering, you can spray a 5-degree stone sulfur mixture on the plant to eliminate the overwintering eggs, shovel the weeds near the flowers and eliminate the insect source. In the aphid danger period, 40% dimethoate or omethoate plus 1200 times water solution for continuous spraying, 3-4 times can be effective.

Scutellaria is one of the most important pests of rhododendron. It often sucks juice near the main vein on the back of the leaf, which forms many oil-stained fields on the back of the leaf, and finally causes the leaf to fall off. The insect is Obovate, about 0.3 mm long, flattened, red, dark red, wood red, irregular black spots on the back and irregular black patches on the side. This insect is most common when it is hot and dry in summer, and then decreases when the rainfall is long.

Control methods spray Baume 0.5 degree stone sulfur mixture once in mid-late October and early spring March respectively to spray 25% insecticidal water swelling agent 500 times the effect is also good.