How to treat the fallen leaves of Magnolia

Mr. Jiang Hongyou wrote to ask: I bought a batch of white orchids from the south in spring and grew luxuriantly in summer and autumn. At the end of October, I entered the greenhouse. When the temperature dropped to-2 ℃ to 3 ℃, I began to heat up with a coal stove, about 25 ℃ to 30 ℃ during the day and more than 10 ℃ at night. On December 15, I watered 12 ℃ cold water, and on the 17th, the flue pipe broke and suffered smoke damage. After 20 days, a large number of Magnolia leaves fell, and five days later, hundreds of pots of Magnolia leaves almost fell out. Excuse me: what is the reason for a large number of fallen leaves of Magnolia? Is there any danger after falling leaves?

Answer: the reason for a large number of fallen leaves of your Magnolia is mainly caused by the smoke in the shed when the tobacco pipe is broken at night. The exhaust gas from coal combustion contains some toxic substances, such as sulfur dioxide, carbon monoxide, some nitrogen oxides, hydrocarbons, etc., as well as more COD, which exceeds the limit that Bailan can bear, and Bailan is particularly sensitive to smoke damage, which will inevitably lead to a large number of leaves falling in a short period of time. Secondly, there may be factors such as low temperature, poor ventilation, or pouring water after the basin soil is too dry, but the possibility of the latter is not very great.

If your Magnolia leaves only fall off, the twigs are not greatly affected, and the terminal bud is still intact, you can pour out one or two white orchids from the basin to see if their roots are necrotic due to asphyxiation. If the buds are healthy, the branches are still green, and the roots are intact, it generally will not have much impact on the growth of the coming year, at least there will be no risk of death.

Take rescue measures: first, should build a perfect double-layer plastic greenhouse, covered with grass curtains or black nets, must maintain the temperature in the shed not less than 0 ℃ to 5 ℃, and the temperature difference between day and night does not exceed 5 ℃ to 8 ℃; if it is necessary to heat up, electric heaters, electric heaters, electric furnaces, etc., if it is really necessary to use coal stove heating, it is necessary to put an end to the waste gas pollution caused by coal combustion, otherwise it must be even worse. Second, when the weather is warmer at noon, properly open the door to breathe, we must keep the air in the shed fresh, but we must prevent the cold wind. Third, the basin soil to maintain moist, not too dry, not too wet, otherwise it is very easy to cause its delicate fleshy fibrous root atrophy and death or rotten root death; watering can be changed to spray, every day with knapsack sprayer to the branches and stems spray, and must ensure that the water temperature is basically the same as the temperature in the shed, avoid too wide disparity, so that it can not stand and suffer new damage. Fourth, when the temperature reaches 10 ℃ to 15 ℃ in the early spring, if a few plants are found to have wrinkled and withered green branches, the branches can be properly shrunk and planted in fresh and loose culture soil. Fifth, because this batch of white orchids have been hurt to a certain extent, they still need less watering and more spraying after coming out of the shed in spring, and only after they draw out new branches and leaves can they be given normal water and fertilizer management.