Cultivation and Management techniques of Magnolia in North China

Magnolia is a deciduous tree of Magnoliaceae, which is native to Jiangxi, Zhejiang, Hunan and other places, and is also widely cultivated in the south of Beijing. Magnolia has white flowers and fragrant flowers. It is an important flowering tree species in the garden in early spring. The cultivation and management techniques in North China are introduced as follows.

Growth habits of Magnolia

Magnolia likes light, is slightly shady, and can be planted under side light, but not under big trees or behind shade. Magnolia is hardy and can safely survive the winter in the open field without measures such as entanglement in the leeward and sunny part of Beijing area. it likes fertile and moist slightly acidic soil, but it can also grow normally in mild saline-alkali soil (pH value 7 to 8.2, salt content less than 0.2%). Magnolia is a fleshy root, afraid of stagnant water, the soil permeability of the planting land is better, sandy loam is suitable.

Selection and planting of seedlings

The selection of seedlings is directly related to the survival rate of planting and the ornamental effect in the future, so we should strictly control the selection of seedlings. In addition to the specifications of seedlings can be determined according to the needs of greening, we should also grasp the following points when selecting seedlings: first, seedlings should not have diseases and insect pests, and trees should be carefully checked to see if there are hyphae, disease spots and decay. Carefully check whether there are insect eyes, live insects, eggs and cocoons. If so, try not to choose. Second, to select good-shaped seedlings, the trunk of the seedlings should be straight, the main branches and lateral branches should be evenly distributed, there should be no partial crown phenomenon, and the top should be kept intact; third, we should pay attention to check whether the tree has skin injuries, such as skin injuries or splitting, it will affect the transport of nutrition and water, which is not conducive to the survival of seedlings. Fourth, after selecting the seedlings, the plants must carry soil balls, the diameter of which is 8 to 10 times of the breast diameter. After the soil balls are dug, they should be tied up with straw ropes to prevent them from breaking up during transportation.

In order to ensure the survival rate of seedlings, more attention should be paid to the following aspects when planting. First, the planting time is the best before the early spring flower; second, the tree pit should be large or not small, which is not only troublesome to plant, but also not conducive to root growth; third, if the soil is too sticky or the pH value is too high, the guest soil should be changed; fourth, the subsoil is preferably mature soil and should be well mixed with base fertilizer. Fifth, the planting depth should be appropriate. Generally speaking, the planting depth of seedlings can be slightly higher than that of the original soil ball by 2 to 3 centimeters. If it is too deep, it is easy to sprout, and if it is too shallow, the roots will be exposed; sixth, large seedlings should be supported in time to prevent them from being tilted by the wind; seventh, after planting, they should be watered immediately, two water after three days and three water after five days.

Magnolia likes to be wet and afraid of waterlogging, so this principle should be strictly grasped in cultivation and maintenance. However, at work, many people think that Magnolia is afraid of waterlogging, so it should be watered as little as possible. Who knows that being afraid of waterlogging does not mean that she likes drought. Magnolia itself likes a moist environment, so how to master this degree? The author believes that in the process of cultivation, the soil should be kept moist without stagnant water. In the process of maintenance, the topsoil of newly planted magnolia must be kept moist, which is also an important measure to ensure its survival rate. After entering the normal management procedure, green water in early spring and anti-freezing water in early winter are indispensable. In other seasons, watering can be determined according to soil moisture and rainfall, and soil moisture conservation should be carried out in time in the rainy season. Irrigation should also be timely during the dry period of the rainy season. Lack of water will not only affect vegetative growth, but also lead to bud shedding or atrophy. It should be mentioned that Magnolia, which is planted in the environment with poor site conditions, especially large hardened area and small green area, should also be sprayed on the leaves while watering the roots in the case of continuous high temperature and drought weather. spray water should pay attention to the degree of atomization, the higher the degree of atomization, the better the effect, the best spraying time before 8 o'clock in the morning and 6 o'clock in the evening, and can not be carried out when the light is strong at noon.

Magnolia likes fertilizer. In addition to applying base fertilizer when planting, topdressing should be carried out every year. Sufficient fertilizer can make the plant grow vigorously, have more flowers and have a long flowering period. Fertilizing Magnolia can be carried out four times a year, that is, applying nitrogen, phosphorus and potassium compound fertilizer before flowering can improve the quality of flowering and is conducive to spring growth; applying nitrogen fertilizer after anthesis can increase plant growth and expand nutritional area; applying phosphorus and potassium compound fertilizer once in July and August can promote flower bud differentiation and improve the Lignification of new branches. Before the beginning of winter, combined with watering winter water to apply a mature fermented ring fertilizer, this fertilizer can improve the activity of the soil, and can effectively increase the soil temperature. In addition, if the seedlings planted in the same year do not grow well, 0.2% potassium dihydrogen phosphate solution can be used for foliar spraying, which can effectively improve the tree potential.

Overwintering management

The overwintering management of Magnolia planted in that year should be strengthened. In addition to timely pouring enough water to seal the frozen water, the tree pits should also be treated with grass mulching, film mulching or soil cultivation, and the trees can be treated with white coating. Magnolia, which has survived for many years, can only be watered with antifreeze water and whitened.

Pest control and pruning

Magnolia is a highly resistant tree species, and the main diseases are black spot, yellowing and leaf burn. Black spot is caused by half-known fungus infection. If it occurs, it can be controlled by foliar spraying with broad-spectrum fungicides such as 70% mancozeb 500 times and 75% chlorothalonil 800 times. During daily maintenance, we should also pay attention to ventilation and light transmission, strengthen water and fertilizer management, and improve plant disease resistance. Chlorosis is a physiological disease, mainly caused by excessive alkali in the soil. Ferrous sulfate (0.2% solution) can be used to adjust the pH, and more farm manure should be applied. There are many causes of leaf burn disease, such as poor site conditions (such as large hardened area, small green area, etc.), long-term high temperature and drought, soil Alkalization or excessive amount of flowers, etc., which can be controlled comprehensively by increasing watering times and applying more fertilizer. Trunk whitening and other measures. Magnolia is occasionally harmed by large coir moth, frost moth and other pests in North China. if it occurs, it can be sprayed with 8000 times of 20% diflubenzuron or 1000 times of zinc and parathion.

Because the callus ability of the branches of Magnolia is poor, it is generally not pruned if it is not necessary, such as the shape of the tree is not beautiful or messy, it can be combined with the actual situation to remove the disease and insect branches, dry and withered branches, overdense branches and useless branches, so as to facilitate the ventilation and light transmission of the plant and the beautiful shape of the tree. The pruning time is carried out before the foliage in early spring. Magnolia generally does not cut short to avoid cutting off flower buds.