What are the correct methods for growing a potted Radermachera sinica (China doll)?

  In its natural state, the Radermachera sinica (China doll) is a medium-sized deciduous tree. Recently, some growers, through careful cultivation, have given it an elegant shape, making it a high-grade potted flower suitable for placement in homes and offices. The roots, leaves and fruit of the Radermachera sinica can be used medicinally, having the effects of cooling the blood, reducing swelling and bringing down fever, and can also treat bruises, venomous snake bites and the like; therefore the "China doll" is increasingly welcomed and recognized by consumers.

  The Radermachera sinica (China doll) is a very good large foliage-type potted plant. In the north, it is generally grown indoors, for example placed in large banquet halls, and more commonly in office spaces. To grow a China doll well indoors, you must also know its growing environment, habits, place of origin and so on; only by understanding and knowing this information can we possibly grow it well indoors in the north.

  Light: The China doll is a light-loving plant, and can survive placed in full sunlight or in a semi-shaded environment, but neither should be extreme. If in summer the sunlight in some areas is too strong, do not expose it to direct blazing sun; if outdoors, you can build a small shed above the China doll, with three sides letting light through and the top shading it, so that at the hottest time the sun cannot scorch it, and when the sun rises or sets the side light shines on it to prevent the China doll from withering from sunscald. If placed in a shady spot for a long time, the China doll will, from long lack of sunlight, have its leaves turn yellow until they fall off.

  Temperature: The China doll originates from tropical and subtropical regions, so naturally it is a plant that likes high temperatures; the most suitable temperature is around 20 degrees, but at most do not exceed 28 degrees, and at minimum do not go below 8 degrees. In summer, if the temperature is higher than 28 degrees, please place the China doll indoors, or inside a shed, preferably ventilated, and spray water on the leaves to help it cool down. In autumn and winter, if the temperature drops below 10 degrees, try as much as possible to place the China doll in an environment with air conditioning or heating, to prevent discomfort or even frostbite from too low a temperature. No matter the season, try as much as possible to keep the China doll living at a suitable temperature.

  Humidity: The China doll likes relatively moist soil and a moist growing environment. Air humidity should generally be kept between 70% and 80%, and at most not exceed 85%. If placed at home, you can often spray the plant with slightly warm clean water to maintain its elegant appearance, and at the same time this can also increase the ambient humidity.

  Water: The China doll likes a relatively moist environment, but the roots must not be soaked in water; keeping the soil moist is enough. Water must not be lacking, but do not overwater, otherwise the tree's roots will rot. In the high-temperature summer season, the plant's water consumption is large, and added to the high temperature, you should often check the soil moisture and replenish water in time, and every 2-3 days spray a little water on the leaves, which increases humidity and also helps lower the temperature.

  Fertilizer: The fertilizer required by the China doll is N : P : K : Ca : Mg = 100 : 9 : 87 : 53 : 12. The EC value of the fertilizer can be 1.6-1.7 mS/cm, and during the plant's rapid growth period it can be increased to 1.9 mS/cm.

  Growth regulators: The high-quality China dolls popular on the market now generally have a height of about 70 cm, a crown width of about 60 cm, an internode length of about 1-3 cm, and a leaf diameter of about 5-7 cm, and with shorter petioles, dense leaves and bright color, they have extremely high ornamental value. To reach this standard, growth regulators must be used; the one used more often is paclobutrazol, at a concentration of 5-50 ppm, applied once at intervals of about one week; the concentration and frequency used can be adjusted according to the weather and the plant's growth, ultimately achieving a reasonable and beautiful plant shape.

  Pest prevention: All plants need pest prevention, only the types of pests to be prevented differ. The main pests the China doll needs to guard against: leaf spot disease, mites, aphids, scale insects and so on. Leaf spot disease, as the name suggests, is when the leaves grow spots; in this case you should promptly remove the leaves, and preferably take them outdoors and burn them in a fire, to prevent other leaves from being infected. Scale insects generally grow on the tree trunk; when found, promptly brush them off and kill them.

  The main cause of the above two diseases is that they breed in a high-temperature, unventilated environment, so ventilation must be ensured. Both of these pests are easy to observe, and if found in the early stage of disease they can be remedied in time. As for mites, they cannot be seen with the naked eye, and aphids are very tiny and not easy to notice without careful observation; the main sign is that when new leaves grow they become wrinkled and curled, and the leaf surface is uneven. You should promptly apply pesticide to eliminate the pests.