How to grow potted white magnolia (Michelia alba)? Cultivation methods and points to note

  White magnolia (Michelia alba) is an evergreen tree with large, lovely flowers that release a delicate fragrance when they bloom; it is a rather precious ornamental plant, and it is also an excellent pollution-resistant landscaping tree species for areas with air pollution. It prefers a warm, humid environment with plenty of sunlight, and does well in well-drained, loose, fertile, slightly acidic soil. Its branches and trunk are upright, its leaves are emerald green, and its form is graceful; its flowers are pure white and elegantly simple, with a fresh, sweet fragrance. In summer it blooms continuously, full of distinctive charm. In northern regions it is mostly grown as a household potted plant.

  Potted white magnolia is neither tolerant of drought nor of waterlogging, and it is not cold-hardy either; for northern regions it is a rather delicate flower. Therefore, the author believes that when cultivating white magnolia, strengthening management in five aspects - watering, light, fertilizing, overwintering and pest control - can be of some help for the care of potted white magnolia. So how do you grow potted white magnolia?

  1. Light

  White magnolia loves light and is not shade-tolerant. Apart from the indoor overwintering period, it must receive sufficient sunlight during its growing period. If it is kept in a shady place for a long time, the branches will grow long and the leaves will be weak, the leaves will easily drop, and the flowers will be sparse and faintly fragrant, affecting its growth. For household potting, note that if the summer is hot and dry for a long time, you can move it to a shady place every day from 11:00 am to 3:00 pm, and increase misting of the leaves and spraying water around the flowerpot, then put it back in a sunny spot for care afterwards.

  2. Watering

  The root system of white magnolia is fleshy; too much water will cause root rot, while too little water will cause the roots to wither. Therefore, watering should follow the principle of preferring less over more, and when you do water, water thoroughly. Generally speaking, in spring white magnolia begins to sprout, so water once every 2-3 days to keep the potting soil loose and moist; in summer white magnolia enters its peak growing season, so water once each morning and evening; if there is a rainstorm or continuous rain, promptly pour out any standing water in the pot; from autumn onwards gradually reduce watering, or water according to how dry or moist the potting soil is - if the surface of the potting soil turns white, water it, and generally watering about once every 5 days is enough; after entering winter, pay special attention to preventing the potting soil of white magnolia from becoming too wet or waterlogged. If you find the leaves of white magnolia turning red and the branch tips turning brown, it means there is standing water at the roots; you should control watering, loosen the soil and strengthen ventilation, generally watering about once every 10 days, keeping the potting soil just slightly moist.

  3. Fertilizing

  White magnolia loves fertilizer. For household potting, fertilizing generally starts in May, once every 10-15 days or so, until after flowering (stopping around September). Generally, on the second day after fertilizing, water once with clear water to help the plant absorb it. Household fertilizing methods are simple and easy: you can mix ferrous sulfate (black alum), cake fertilizer and water in a ratio of 1:5:100, put it in a crock and let it fully ferment and decompose, and it is ready; for the cake fertilizer, either soybean cake or peanut cake can be used. After white magnolia forms buds, it should also be given 1-2 additional applications of monopotassium phosphate, which helps flowering. During fertilizing, if the leaves of white magnolia are oily green and glossy, it means the fertilizing is reasonable; if the top leaves are dark green and some leaves are wrinkled and not spreading out, it means too much fertilizer has been applied, and fertilizing should be stopped immediately.

  4. Pruning

  For potted white magnolia, choose a suitable height, and use pruning shears to cut off the terminal buds and shorten some side branches. Cutting off the terminal buds helps more side branches to grow, resulting in more buds and more flowers. White magnolia has weak sprouting ability, so generally the vegetative branches are not pruned, but it is necessary to cut off dead branches and diseased or pest-infested branches. During the bud stage, appropriately remove some leaves to help bud formation, which can make the buds larger and the flowering period longer. In summer, when white magnolia grows vigorously, choose a spot 3-5 cm where new shoots have grown and prune there; after pruning, immediately seal the wound with a mud ball mixed with fungicide and auxin, and wrap it tightly on the outside with a small plastic film.

  5. Repotting

  According to the size of the white magnolia's canopy and the length of its age, replace it with a suitably sized pot or tub to promote vigorous growth. When doing this, wait until the potting soil is slightly dry, slowly tilt the pot (or tub) (or turn it upside down), support the pot with one hand, grip the plant firmly with the other, and tip the white magnolia out into the new pot. The new pot (or tub) should first have a small amount of loose soil placed in it, then water thoroughly right away, and once it is planted stably it is fine. White magnolia is generally repotted once every 2 years, and each repotting should use a pot one size larger; repotting can be done in spring after it is taken out of the shed. The new pot should be disinfected and de-fired; use broken tile pieces at the bottom of the pot to make a drainage layer, spread about 3 cm of growing soil on the drainage layer, then put in 3 to 4 pieces of horseshoe slices as base fertilizer, then spread another layer of growing soil, knock the plant out of the original pot, cut off the dead roots and rotten roots, then put it into the new pot, fill in soil layer by layer and press it firm, then water thoroughly once right away.

  6. Overwintering

  White magnolia has poor cold tolerance, so overwintering management for household potting is very important. Generally, before Frost's Descent (mid-October) it needs to be moved indoors to overwinter, and placed in a sunny spot indoors. Keep the daytime temperature at 12°C and the nighttime temperature no lower than 6°C, otherwise it is prone to frost damage or leaf drop.

  To ensure white magnolia overwinters safely, pay attention to four points when caring for it indoors: ① Pay attention to whether there are gaps around the doors and windows near the white magnolia; if the doors and windows do not close tightly and there is draft, it will cause leaf drop, so this should be avoided. ② White magnolia has poor resistance to smoke and dust, so it is best not to keep it in the same room as a coal stove. ③ Frequently spray-wash and wipe the leaves with warm water (15°C-20°C), which not only keeps the leaves emerald green and beautiful but also increases humidity. ④ Pay attention to strictly controlling the amount of water given to white magnolia during overwintering, watering only when the soil looks dry.

  In northern regions, potted white magnolia often shows leaf drop during the overwintering period. Growers need not be nervous; promptly move it to a place with a higher room temperature and sufficient light, or raise the indoor temperature. As long as its root system has not been frost-damaged, once the temperature rises in spring it can recover its vigour. Generally in mid-April, when the temperature is 15°C-18°C, white magnolia can be moved outdoors to a sunny spot for care.

  7. Pest and disease control

  The main insect pests harming white magnolia are red spider mites, scale insects and so on. Red spider mites often suck the sap of white magnolia; in mild cases they make the leaves turn yellow, and in severe cases they cause the plant to die, and their secretions can also induce sooty mould and many other diseases. Therefore, during household care, pay attention to daily observation; when you find abnormal leaf colour, carefully check the underside of the leaves. If only a few leaves are affected, remove the infested leaves; when more leaves are affected, spray with a 1000-fold solution of dicofol for control. As soon as scale insects are found, immediately scrape them off with a bamboo strip.

  White magnolia is prone to chlorosis, caused by soil and water being on the alkaline side. You can spray the leaf surface with a 0.2% ferrous sulfate aqueous solution, once every 5-7 days, and you can also regularly apply fertilizer water mixed from ferrous sulfate and cake fertilizer to prevent it. For anthracnose of white magnolia, at first the leaves lose their green colour and show small yellow spots, which then gradually expand into round shapes; in severe cases the leaves scorch, turn black and drop off. When it occurs, use a 50% carbendazim wettable powder 800-fold solution for control, spraying once every 10 days or so.

  For household care, in order to prevent pests and diseases, before white magnolia is brought indoors, prune it once, cutting away diseased and dead branches, leggy branches and overly dense branches, and spray once with a 1000-fold solution of lime sulfur, which can have a preventive effect.