How to Plant and Maintain Magnolia
Today, our editor introduces the planting and maintenance of magnolia, as well as the knowledge content of magnolia cultivation techniques in terms of flowers and plants. The specific introduction is as follows:
Magnolia is a plant of the Magnolia family, usually a deciduous tree, straight stem and wide branches, often flowering before leaves, large and fragrant flowers, which is a good material for landscaping. Magnolia is only distributed in our country, its flowers, leaves and fruits are all distinctive, with ornamental value, now widely used in gardens. However, with the strengthening of human activities, the living environment of magnolia has been destroyed, and the natural reproduction rate is not high, so it is listed as a near-endangered species. Many magnolias have strong resistance to toxic gases such as SO2, and the application in gardens can effectively improve the environment. Magnolia also has certain medicinal value, and its dried flower buds have the effects of stopping headache, relieving sinusitis, lowering blood pressure, etc. Magnolia flowers contain citral, eugenol acid and other volatile oils, which can be used to dispel wind and cold, promote nasal and lung. Modern research has found that magnolia flowers can also be used to inhibit some common skin fungi. Magnolia has a fragrance, contains essential oils, and is often used to extract and make perfumes, etc. Its seeds can be used to extract oil for industrial use. The branches and trunks of magnolia are straight, the texture is delicate, and it is an excellent material for making furniture.
1 Characteristics and Garden Applications of Different Magnolia Varieties
1.1 White Magnolia
White magnolia, generally known as Yingchun flower, Yingchun flower, etc., is native to Java, Indonesia, and is a plant of the Magnolia family. It is a tree, with a height of up to 25m and a diameter of up to 1m, with deciduous leaves in autumn, a large crown, dark gray bark, gray-brown twigs, and paper-like obovate leaves. The flowers are white with often pink at the base, cylindrical aggregate fruits, and heart-shaped seeds. The flowers have a strong fragrance and usually bloom from February to April (often blooming again from July to September), with fruiting in August to September. It has strong adaptability, grows fast, likes light and humid environment, but not high temperature exposure, has a certain shade tolerance, and has good cold resistance, and can grow normally in the range of -20~40℃. White magnolia is a famous ornamental tree in China, the city flower of Shanghai, with a cultivation history of more than 2500 years, and is now widely planted and applied in gardens, with diverse cultivation methods, which can be planted alone to form a landscape, or planted in patches or rows, or used as street trees. White magnolia has a high affinity with many other Magnolia family plants and can be used as a rootstock for grafting to improve the adaptability of other Magnolia family tree species.
1.2 Erqiao Magnolia
Erqiao magnolia, native to our country, is a plant of the Magnolia family and is a variety obtained by artificial hybridization of white magnolia and purple magnolia, also the first variety in the world to obtain the genetic traits of white magnolia. Erqiao magnolia is a small tree, with a height of up to 10m, deciduous, with obovate leaves, with soft hair on the back of the leaves, no hair on the small branches, large flowers, bell-shaped, often opening before the leaves, fragrant, blooming from March to April, with flowers ranging from light red to deep red. The key to distinguishing Erqiao magnolia is to observe whether it has petal lobes of different sizes and shapes, generally the outer petals are shorter. The fruiting period is from September to October, with black fruits and dark brown, obovate seeds. Erqiao magnolia grows fast, has a wide range of adaptability, is cold and drought tolerant, with many species, which have been introduced and cultivated in many countries and regions, and can grow well. Erqiao magnolia has a sparse tree shape, fewer branches, smaller leaves, and often yellow, which needs to grow in well-ventilated, fertile, humid, and well-drained slightly acidic sandy loam.
1.3 Purple Magnolia
Purple magnolia, native to our country, is a plant of the Magnolia family, also known as Magnolia, Xinyi. Purple magnolia is a deciduous shrub, about 3m high, with gray-brown bark, green-purple or light purple-brown small branches, elliptical obovate or obovate leaves, flowers and leaves open at the same time, flowers are bottle-shaped, purple or purplish red, not fragrant, fruits are dark purplish brown aggregate fruits, with short beaks at the top of the mature follicles.
Purple magnolia blooms from March to April and fruits from August to September. It is suitable for growth in warm, humid, sunny environments, can resist wind, has few diseases and pests, but is not resistant to cold, drought, saline-alkali, and is not resistant to transplantation. Purple magnolia has low overall adaptability, difficult maintenance, is a very precious tree species, and is listed on the Red List of Plants of the International Union for Conservation of Nature (IUCN), belonging to vulnerable plants. Purple magnolia has a wide range of garden uses, which can be used for courtyard greening and ornamental, planted alone or scattered, can also be used with orchid plants to create scenery, and can also be used for road greening, park greening or house hall beautification.
1.4 Red Magnolia
Red magnolia, native to Wufeng County, Hubei Province, is a new species discovered by Professor Ma Luyi's research team, Magnolia family Magnolia genus, also known as Wufeng magnolia. Its distribution range is narrow, mainly distributed in the central and western parts of Wufeng County and its junction with Changyang County, which is a unique variety in the Three Gorges area and a rare tree species. Red magnolia is an arbor, which can grow up to 30m high, deciduous, with gray-brown bark, gray-white when young, obovate leaves, short and soft hair on the petioles, obovate spatulate flowers, red or dark red in color, flowers open before leaves, cylindrical aggregate fruits, and red fruits. Red magnolia is divided into 3 color systems, namely deep red system, red system, light red system, and the flower shape can be divided into peony type, lotus type, rose type, etc., which is an extremely excellent garden ornamental flowering tree species, with high ornamental and scientific research value. Red magnolia has good cold resistance, likes humid and cool environment, can grow under -20℃ conditions, suitable for loose and fertile soil with good drainage, generally requiring pH value of 4.5~6.5.
1.5 Guang Magnolia
Guang magnolia, native to the southeastern part of North America, is a plant of the North American Magnolia genus of the Magnolia family, also known as lotus magnolia, foreign magnolia. Guang magnolia is a tall and large tree, up to 30m high, evergreen, with gray or light brown bark, deep green elliptical leaves, leathery, large and white flowers, single flower diameter up to 20cm, resembling lotus flowers, cylindrical aggregate fruits, oval seeds, blooming period in May to June, fruiting period in September to October. Guang magnolia is suitable for growth in warm and humid environment, with certain cold resistance, can survive in -19℃ environment, but long-term exposure to temperatures below -12℃ will cause leaf frost damage. Its growth rate is moderate, not resistant to pruning, drought-resistant, poor-resistant, smog-resistant, pollution-resistant, and disease and pest-resistant, which is a long-lived tree species. Guang magnolia has a wide adaptability and can grow in fertile, humid, and well-drained slightly acidic or neutral soil, but grows poorly in calcareous soil. Its roots are deep and wide, with developed lateral roots, especially wind-resistant. Because of its excellent characteristics, it is widely used in landscaping, often planted alone in flower beds, lawns, or with other plants to form landscape communities.
1.6 Feihuang Magnolia
Feihuang magnolia is a bud mutation variety selected from the natural mutation of white magnolia, with pure yellow flowers, belonging to the Magnolia family Magnolia genus deciduous tree, with light yellow-green young branches, robust with short and soft hair, thick paper-like obovate leaves, obvious petioles, yellow to light yellow thick and fleshy flowers, flowering later, often in April, cylindrical aggregate fruits. Feihuang magnolia is distributed in central China, likes light, has high cold and drought resistance, likes fertile, humid, and well-drained acidic soil, with developed root growth, not resistant to waterlogging. Its buds can be used as "Xinyi" for medicinal use, and can also be used to extract fragrances. Feihuang magnolia grows fast, has strong adaptability and wind resistance, few diseases and pests, strong cold and pollution resistance, and high ornamental value. Currently, Feihuang magnolia is less widely used, and in-depth exploration has great market application potential.
2 Propagation Methods
The propagation methods of white magnolia include cutting, sowing, grafting, layering and others, generally more with grafting and layering. The propagation of Erqiao magnolia mainly relies on sowing and grafting. Purple magnolia can be propagated through sowing, layering, division, cutting, grafting and other methods, and can also be rapidly propagated through tissue culture. Among them, layering propagation has a high survival rate, and grafting is the most commonly used method. Red magnolia was discovered later and has few resources available. At present, the research progress of seedling breeding is slow. It can be propagated through sowing, grafting, cutting, tissue culture and other methods. The most efficient way is cutting propagation. Guang magnolia often adopts grafting, sowing and cutting propagation. Among them, grafting is the most commonly used and has the highest survival rate. Feihuang magnolia is generally propagated by grafting, with the highest survival rate of 2-year-old rootstocks. Lechang Hanxiao and Wangchun magnolia can also be used as rootstocks, with high survival rate of branch grafting, and bud grafting can also be used.
3 Shaping and Pruning
Magnolia branches and trunks are not easy to heal after injury, so it is not resistant to pruning, and pruning should be minimized in management. However, in order to maintain the tree shape, maintain health, and ensure normal flowering, reasonable pruning should be carried out according to the growth situation. Generally, after the magnolia germinates in early spring and after the top is sealed in late autumn, diseased and insect branches, dead branches, and weak branches are cut off; in June to July in summer, excessive branches, overlapping and intersecting branches, inner branches, and drooping branches are trimmed appropriately according to the overall growth of seedlings, so as not to affect the overall tree shape; after flowering, residual flowers and fruit spikes are cleaned up in time, except for those left for seeds.
In addition, pruning should be carried out according to specific application methods. The trunk of road greening should be at least 2m high. If used for garden landscape or courtyard planting, the trunk can be appropriately low, about 1m. The branches of white magnolia grow fast, so the fast-growing main branches need to be pruned to ensure the growth of lateral branches and maintain the tree shape. Erqiao magnolia does not need pruning unless necessary. In order to avoid cutting off flower buds, short pruning is generally not performed. In the management of purple magnolia, short pruning is generally not performed, and attention should be paid to avoid pruning before flowering, so as to avoid leaving dead stubs. Large Guang magnolia trees can be pruned by removing leaves, generally removing 1/3. In the pruning of Guang magnolia, 2~3 lateral branches are retained for each main branch, and all other small branches and lateral branches should be cut off to maintain the tree shape.
4 Soil, Fertilizer and Water Management
Magnolia is a plant that likes moisture, not drought-resistant, and not waterlogging-resistant. When planting, choose a place with relatively high terrain, otherwise it is easy to rot the roots due to waterlogging. Daily watering should maintain an appropriate amount, keep the soil moist, and never overwater. In rainy season, accumulated water should be drained in time. In summer, to ensure the growth needs, a large amount of water should be watered multiple times, avoiding the high temperature period of solar radiation at noon. After autumn, the water demand decreases, and the frequency and amount of watering should be reduced to delay root growth and promote branch maturity. Magnolia is a plant that likes fertilizer, but it cannot be over-fertilized.
Usually, fertilization is required 4 times a year. The first time is before flowering in spring to promote growth, improve the quality of flowering, and apply nitrogen, phosphorus and potassium compound fertilizer once; after flowering, to increase the growth of plants and increase the nutritional area, apply nitrogen fertilizer once; in autumn, when the plants are in the critical period of flower bud differentiation and lignification of new branches, phosphorus and potassium compound fertilizer can be applied once; before winter, when freezing water is poured, decomposed and fermented organic fertilizer can be applied once to enhance soil activity and increase ground temperature, ensuring overwintering and later growth. For seedlings newly transplanted in the same year, when the growth is too weak, 0.2% monopotassium dihydrogen phosphate can be sprayed on the leaf surface to promote rapid growth. Fertilization should be applied reasonably according to the growth of the plants. Generally, less fertilizer should be applied to newly transplanted seedlings, and the amount and frequency of fertilization can be appropriately increased during the growing period. When fertilizing, the fertilizer can be dissolved in water for irrigation, or fertilization can be performed on rainy days, which is more conducive to fertilizer absorption.
5 Pest and Disease Control
White magnolia is more troubled by pests and diseases, common diseases include anthracnose, leaf spot disease, etc., and common insect pests include red spider, longicorn beetle, etc. Erqiao magnolia has strong resistance to pests and diseases, mainly with black spot disease, leaf burn disease, yellowing disease, etc., and pest insects such as large bagworm moth, frost moth, etc. The main diseases of purple magnolia are yellowing disease, and root rot disease in the seedling stage, and pest insects such as large bagworm moth, red spider, wireworm, etc. The seedling stage of red magnolia is more prone to root rot disease, and the insect pests that have a greater impact on red magnolia include tussock moth, mealybug, leaf mite, longicorn beetle, etc. The main diseases of Guang magnolia are anthracnose and stem rot disease, and the main insect pests are scale insects and leaf roller moth.
Pest and disease control is mainly prevention, early detection and early treatment, and the use of chemical agents should be cautious. If the area of pest and disease occurrence is small and the impact on plants is small, some do not need treatment or medication, and some can be removed by physical methods. In daily maintenance, management should be strengthened to ensure the health of plants and improve their resistance to pests and diseases; attention should be paid to ventilation and light transmission, and diseased leaves and dead branches should be cleared in time.
When pest and disease treatment is required, the following agents are often used: during the high incidence period of anthracnose in high temperature in summer, 50% chlorothalonil 800 times liquid or 50% carbendazim 500 times liquid can be used for prevention and treatment after onset. Black spot disease can be controlled by spraying 70% Daishen Forest manganese zinc 500 times liquid or 75% chlorothalonil 800 times liquid on the leaf surface. Yellowing disease is generally caused by excessive soil alkalinity, mainly controlled by adjusting acid-base, generally spraying 0.2% ferrous sulfate solution or applying more farmyard manure. After leaf burn disease occurs, water and fertilizer should be applied in time, and tree trunk whitewashing should be performed at the same time. Stem rot disease is mainly prevention. After pruning, protective agent should be applied to the cut surface in time. If the disease occurs, 70% methyl thiophanate 800 times liquid can be applied. Root rot disease can be treated with a variety of agents such as forest manganese zinc and Fumigatin. In order to avoid drug resistance, a single agent should not be repeatedly applied during the control process.
Pest control, large bagworm moth, frost moth, etc., can be controlled by 20% chlorfenapyr 8000 times liquid or 50% phosphorus sulfide 1000 times liquid; red spider can be killed by 5% Nisolan 2000 times liquid; longicorn beetle can be killed by 500 times liquid of color Virelay; wireworm can be killed by 50% zinc phosphide emulsion 1000 times liquid. Scale insects can be killed by spraying acetamiprid and chlorpyrifos or only spraying pyrethroid insecticides. The leaf roller moth occurs from April to May and can be controlled by spraying 90% trichlorfon crystal 1000 times liquid for 2~3 consecutive times.
6 Conclusion
Magnolia species are rich, the tree posture is beautiful, the flowers are bright and large, and can effectively absorb harmful gases, which is a tree species with high ornamental value. It is widely used in the construction of gardens in various cities, and the commonly used varieties are relatively fixed. There are certain differences in morphological characteristics and growth habits of different varieties. In practical use, it is often due to the lack of understanding of the growth characteristics of different varieties of magnolia, and the selection of planting sites and management methods are not in place, which is not conducive to their good growth. At present, many scholars have carried out extensive research on various varieties such as white magnolia and purple magnolia. This study systematically summarizes the ecological habits and management methods of different varieties of magnolia, so as to make more reasonable and effective use of them.
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