Cultivation and Management of Magnolia Magnolia

Magnolia, also known as Magnolia, Yutangchun, Muhuashu, Magnolia deciduous trees, native to Anhui, Zhejiang, Hunan, Hubei, Guizhou, Guangdong, Shanxi and other regions, in Beijing and south of the region is also widely cultivated. Magnolia white color, flower big flavor fragrance, is an important garden early spring flower species, deeply loved by people, and begonia, spring, peony, osmanthus planting, auspicious, rich meaning, and "Yutang spring rich" reputation. The cultivation and management techniques of Magnolia are described as follows for reference only.

1. Common ornamental tree species in the same genus

There are about 90 species of Magnolia in Magnoliaceae, about 30 species in China. The common species and cultivated varieties in gardens are Magnolia denudata acv.Feihuang, Magnolia iliflora Desr., Magnolia biondi amp. Magnolia soulange (Lindl.) Soul.- Bod.）、Magnolia denudate var. purpurascens Rehd.etwils etc.

Second, the choice of planting environment

Magnolia love light, young trees more shade, not resistant to strong light and sun, too strong light or sun, easy to make trees burned. Magnolia can be planted in the lateral light environment, planted under the tree or in the shade will grow poorly, thin tree, sparse branches, small leaves and yellow, no flowers or small flowers; Magnolia is more cold-resistant, able to withstand short-term low temperature of-20℃, but should not be planted in the wind, otherwise easy to shoot, in Beijing area leeward sunny place without winding measures can safely winter in the open field; Magnolia likes fertile, moist, well-drained slightly acidic soil, but can also grow normally in mild saline-alkali soil (pH 8.2, salt content 0.2%); Magnolia is a fleshy root, afraid of ponding, planting terrain should be high, planting in low-lying places is easy to rot roots and lead to death; Magnolia planting land soil permeability is also good, planting in clay is poor, in sandy loam and yellow soil growth best.

III. Digging and planting of seedlings

Magnolia is not resistant to transplantation, generally 10 to 15 days before germination or flower just withered and not open leaves when transplanting is ideal. 4 to 5 days before the seedlings to irrigate a permeable water, this can not only make the plants absorb sufficient water, conducive to survival after planting, but also conducive to digging seedlings into the soil ball. In the excavation to minimize damage to the root system, root wounds must be smooth, in order to facilitate wound healing, but also need to pay attention to: no matter how large the size of the seedlings should be with soil ball, soil ball diameter should be 8 to 10 times the diameter of the seedlings, not too small, too small will not protect the root system. After the earth ball is dug, it should be tied up with straw rope to prevent it from scattering during transportation.

Before planting, the tree pit should be dug well. The tree pit should be large rather than small. If the tree pit is too small, it will not only be troublesome to plant, but also unfavorable for root growth. The soil at the bottom of the tree pit should be mature soil. If the soil is too viscous or pH value or salt content exceeds the standard, it should be treated or improved. Cultivated soil permeability must be good, soil fertility must be sufficient, to be able to supply enough nutrients to plants, soil can not have bricks, tiles, lime and other impurities. Planting depth should be appropriate, generally speaking, planting depth can be slightly higher than the original soil ball 2 to 3 cm, too deep is easy to produce stuffy buds, too shallow will make the roots bare, but also easy to be blown down by the wind. Large-sized seedlings should be set up in time with triangular supports to prevent them from being tilted by wind; after planting, they should be watered immediately, watered twice after 3 days, watered with three water after 5 days, and then entered into normal management. If the seedlings planted with buds, buds should be cut off to prevent flowering and fruiting consume a lot of nutrients and affect the survival rate.

IV. Water and fertilizer management

Magnolia has neither waterlogging nor drought tolerance, so the principle of "liking wet and fearing waterlogging" should be strictly observed in cultivation and maintenance. In the process of cultivation and maintenance, many people think that Magnolia is afraid of waterlogging and should be watered as little as possible. This understanding and practice is very wrong, because Magnolia is afraid of waterlogging and does not mean that it likes drought. It itself likes humid environment. In terms of water management, it is necessary to master the degree that the soil cannot be too dry or too wet. After years of cultivation practice, the author thinks that in the cultivation process, the soil should be kept moist without ponding. During the conservation process, newly planted Magnolia should keep the soil moist, which is also an important measure to ensure its survival rate. To enter the normal management of magnolia watering, early spring green water, early winter antifreeze water is indispensable, but also to irrigate fully, in the growing season, can be irrigated once a month, the rainy season should stop watering, after the rain to timely drainage, to prevent due to ponding caused by rotten roots, in addition, should also be timely loose soil preservation. It should be noted that irrigation should also be carried out in time during the rainy season and drought period. Water shortage not only affects the vegetative growth of plants, but also causes flower buds to fall off or shrink, affecting the flowering of the following year.

In addition, in poor site conditions, especially hardening area, green space area of small environment planted Magnolia, in the case of continuous high temperature and drought weather, watering at the roots should also be given foliar spray, spray should pay attention to the degree of atomization, the higher the degree of atomization, the better the effect, spray time to 8:00 in the morning and 6:00 in the evening after the best effect, noon strong light can not be carried out. For Magnolia suffered from waterlogging, it is necessary to save it at the first time. First, the accumulated water should be removed in time. Second, shade the tree body, especially to prevent the sun from shining in the west. Third, cut off some leaves and buds.

Magnolia love fertilizer, in addition to planting base fertilizer, fertilizer should be applied every year thereafter, fertilizer sufficient to make the plant grow vigorously, leaves green hypertrophy, not only with more buds, but also large flowers, long flowering and fragrant. Fertilizing Magnolia denudata is carried out four times a year, i.e. applying nitrogen, phosphorus and potassium compound fertilizer once before flowering, which can not only improve flowering quality, but also facilitate spring growth; applying nitrogen fertilizer once after flowering, which can improve plant growth and expand nutrient area; applying phosphorus and potassium compound fertilizer once in July and August, which can promote flower bud differentiation and improve lignification degree of new branches; Before winter combined with irrigation winter water and then apply a decomposed fermented fertilizer, this fertilizer can not only improve the activity of the soil, but also effectively improve the ground temperature, and the amount of fertilizer should be large should not be small. In addition, if the seedlings planted in the same year grow poorly, they can be sprayed with 0.2% potassium dihydrogen phosphate solution, which can effectively enhance the tree vigor.

V. Overwintering management

Although the monarch can withstand the low temperature of-20℃, the small size monarch and the monarch planted in the same year should strengthen the winter management. In addition to watering the frozen water after the defoliation in the middle and late November, the tree pit should also be covered with grass, film or soil treatment, and the tree body can be painted white to prevent shooting in spring. Magnolia planted for many years can only be treated by pouring antifreeze water and painting white.

VI. Pest Control

1. Disease Magnolia is a tree species with strong disease resistance. The main diseases are anthracnose, chlorosis and leaf burn.

(1) Symptoms and rules of anthracnose: anthracnose mainly harms the leaves of Magnolia. Irregular spots appeared from leaf tip or leaf margin, or round spots appeared on leaf surface. At the initial stage, the spots were brown and water-stained, with small black particles on the surface and dark brown raised lines on the edges, clearly demarcated from healthy parts. Anthracnose bacteria overwinter on trees or leaves as mycelium, produce conidia in the spring of the following year, spread to plants by wind and rain, spores germinate in water drops, invade leaf tissues and cause disease. In summer, high temperature and high humidity period is the peak period of disease. Plant water and fertilizer management is not in place, dense ventilation, growth decline is very easy to occur this disease.

Control methods: strengthen water and fertilizer management, enhance tree vigor, improve disease resistance; timely remove diseased leaves, remove fallen leaves at the end of autumn and burn them intensively; if there is disease, spray 800 times solution of 75% chlorothalonil wettable particles or 500 times solution of 70% anthrax, once every 10 days, continuously spray 3 to 4 times to effectively control the disease. Special effect chemicals: penkejun, kresoxim-methyl, amicta, etc. on fungal diseases caused by special effects.

(2) Symptoms and rules of chlorosis: first, the leaves are chlorotic, chlorophyll gradually decreases, the leaves are yellow or light yellow, the veins are still green, the whole leaves turn yellow after the disease expands, and then gradually turn white, the plant growth gradually declines, and finally dies.

Control methods: chlorosis is a physiological disease, mainly caused by soil viscosity, pH value exceeds the standard, iron element supply is insufficient. Can use 0.2% ferrous sulfate solution to irrigate roots, can also use 0.1% ferrous sulfate solution for leaf spray, and should apply more farm manure.

(3) Symptoms and rules of leaf burn disease: At the initial stage, the leaves of the plants were scorched, and then the leaves gradually shrank and dried up. When the disease was serious, the new leaves could not be unfolded, and a large number of leaves dried up and fell off. This disease often occurs under poor site conditions, such as large hardening area, small green area, long time high temperature, drought, too strong light, soil alkalization or excessive flower amount.

Control methods: increase watering frequency, keep soil moist; apply more organic fertilizer, enhance tree vigor, improve plant resistance; paint white or wind dry trees.

2. The main pests that harm magnolia are: big clover moth, frost day moth, red spider, longicorn, etc., but also occasionally underground pests such as grub harm. If there are pests, 80% dichlorvos EC 800 times or 50% fenitrothion EC 800 times can be used to kill large moth; Bt emulsion 800 times or 50% fenitrothion EC 800 times can be used to kill frost moth; 40% dicofol 800 times or 5% nisolon 2000 times can be used to kill red spider; green Weilai 500 times can be used to kill longicorn beetle; 50% zinc thiophos emulsion 1000 times can be used to kill white grubs by root irrigation.

VII. Trimming and shaping

Because the callus ability of Magnolia branches is poor, it is generally not pruned if it is not necessary. If the tree shape is not beautiful or chaotic, the diseased branches, withered branches, drooping branches and excessive branches, over-dense branches and useless branches should be thinned out to facilitate ventilation and light transmission of the plants. The tree shape is beautiful. Pruning is done in early spring before leaf opening. Magnolia generally do not cut short, so as not to cut flower buds. If trimming is required, apply Bordeaux mixture to larger wounds to prevent infection.