How to grow azaleas? A full breakdown of cultivation and management key points
(1) Potting and repotting: Use yellow mud + leaf mold as the main components, mix in a little river sand as the growing medium, ensure the soil is on the acidic side, and avoid heavy clay soil. When first potting, choose as small a pot as possible, then gradually move to larger pots; azaleas do not need repotting every year, and repotting and soil replacement should only be considered when the roots have filled the pot and water no longer drains out easily.
(2) Cutting propagation: The plum rain season is the best time for cuttings, when the new azalea shoots are already semi-lignified and the temperature and humidity are suitable, which is very favorable for the rooting and survival of the cuttings. Take healthy new shoots about 5-7 cm long, remove the lower leaves, keep 3-4 top leaves, and use mountain soil mixed with yellow sand as the substrate for the cutting bed. Pay attention to shading and frequent misting; roots will form after about one month.
(3) Grafting propagation: Rhododendron mucronatum is often used as the rootstock, and varieties such as Western azaleas that are difficult to root from cuttings are propagated by grafting, mostly using cleft grafting, approach grafting, or cut grafting. For example, in cleft grafting, cut the top bud of the rootstock flat, make a cut in the center, then cut a scion about 1 cm long with a bud head, whittle both sides into a wedge shape, insert it into the rootstock, tie it securely, and cover the outside with plastic film.
July to August
(1) Shading: Azaleas prefer a semi-shaded environment; provide shade in summer to prevent sunscald and excessively high temperatures. (2) Watering: Azaleas prefer a slightly moist environment; watering is best done in the evening, and during hot seasons leaf misting should also be increased and the humidity of the surrounding environment raised, but be careful not to let the potting soil become too dry or too wet, so as to avoid leaf drop or root rot; in addition, also pay attention to regularly using slightly acidic water.
September to October
(1) Fertilizing: As the temperature drops, apply topdressing 2-3 times, with special emphasis on fully rotted poultry manure fertilizer rich in phosphorus, to promote plump flower buds and larger blooms the following year. Fertilizing is generally done in the evening, and on the following morning apply a "return watering" to speed up the dissolution of fertilizer in the potting soil and prevent fertilizer burn.
(2) Seedling-stage management: Gradually remove the shade netting to increase light; apply dilute fertilizer water to promote seedling growth; watch out for autumn drought and continue misting the leaves.
November to February of the following year
(1) Cold protection and overwintering: Clean up the plants, spread fully rotted compost as a base fertilizer, and earth up the soil for cold protection.
(2) Watering: Keep the potting soil merely moist; avoid its being too wet, otherwise root rot easily occurs.
(3) Flowering regulation: Move potted plants into a greenhouse, place them in sunlight, sprinkle a suitable amount of water on the top each day, keep them at 8-10 degrees, and after the flower buds show a slight color, raise the temperature to 15-20 degrees, and they can bloom at Spring Festival. If, before bud break in early spring, they are placed in cold storage at 3-4 degrees, then moved outdoors in summer and autumn, they will bloom after 2 weeks.
March to April
(1) Fertilizing: As the temperature rises, both before and after flowering are the best periods for fertilizing azaleas. When fertilizing, grasp the principle of preferring dilute over concentrated and less over more, and apply light fertilizer frequently. Commonly use dilute, fully rotted soybean cake water or manure fertilizer, and try not to use chemical fertilizers. The amount of fertilizer can be adjusted according to changes in leaf color; generally, with proper fertilizing, the leaves are dark green; if the fertilizer is excessive, the leaves droop and even the leaf tips begin to scorch.
(2) Preventing and treating physiological diseases: Apart from being prone to red spider mites during hot and dry seasons (which can be killed by spraying with a 1500-fold dimethoate solution), azaleas have no other serious pests or diseases, but they are prone to physiological yellowing due to iron deficiency. This can be addressed by replacing the potting soil and using black mountain soil for planting; or by applying ferrous sulfate mixed with humus and incorporated into manure fertilizer; also pay attention to moderating watering, improving the air permeability of the potting soil, and appropriately increasing light and ventilation and other management measures.