The main points of rhododendron cultivation

Rhododendron is one of the top ten traditional flowers in China, which is rich in shape, colorful and beautiful. However, cuckoos have higher requirements on the growth environment. If they are not managed properly, their growth and flowering are often unsatisfactory, and even wither and die. Therefore, in the cultivation of rhododendron, we should pay attention to the following six points.

First, soil. Rhododendron prefers acid soil with loose, strong ventilation, good drainage, pH between 5 and 6.5 and rich in humus. Mountain mud is the most suitable, and rotten leaf soil, pine needle soil, peat soil or rotten sawdust can also be used. Avoid alkaline soil or clayey soil with poor drainage.

Second, temperature. Cuckoos like warm and cool climate, and most cuckoos have a certain degree of cold resistance. The optimum temperature for its growth is from 12 ℃ to 25 ℃. It grows slowly or semi-dormant when the temperature exceeds 30 ℃, enters dormancy when the temperature is lower than 5 ℃, and frost injury occurs when the temperature is lower than ~ 3 ℃.

Third, moisture. The cuckoo root system is shallow and developed, the root hair is as thin as hair, is very sensitive to water, afraid of drought and waterlogging. It is generally required that the soil water holding capacity is not less than 18%, but if there is stagnant water in the basin, rotten roots will die, so how much water is the key to raising azaleas. Generally speaking, it should be flexibly mastered according to the season, weather conditions, plant size, dry and wet soil, growth and development. When the temperature drops in winter, the cuckoo grows slowly and needs less water, so the amount of water should be reduced appropriately; when the temperature rises in spring, the water demand increases when the cuckoo blossoms and shoots; in the high temperature season in summer, water should be sprayed on the ground and leaves at noon and evening to cool and humidify; when the weather turns cool in autumn, watering should be reduced to prevent secondary growth, which is disadvantageous to overwintering. From the growth and development point of view, the vegetative growth stage of water demand, flower bud formation stage should be less watering, more watering will make branches and leaves grow, flower buds reduced. It is not easy to water more after the flower bud is formed, in case the top of the flower bud opens and does not bloom the following year. Neutral or slightly acidic Rain Water, river and pond water are the best for watering. If tap water is used, it is best to store it in a tank for 1 to 2 days and wait for chlorine to evaporate before use. Long-term watering will reduce the acidity of the soil, so 0.2% ferrous sulfate can be added every 5 days. Or add a little vinegar and water it every half a month to make sure the soil is slightly acidic.

Fourth, fertilizing. Cuckoos like fertilizer, so they should grasp the principle of "applying thin fertilizer frequently". Rhododendron root system is thin and dense, the ability to absorb fertilizer is poor, do not apply thick fertilizer or raw fertilizer. Commonly used fertilizers include rotten cake fertilizer, fish meal or bean juice. It takes about 8 to 9 months for rhododendron to differentiate from flower bud to blossom. Rational fertilization is the key link to make rhododendron blossom. The specific fertilization methods are as follows:

After flowering, cuckoos should apply nitrogen-based fertilizer 2 to 3 times, once every 10 days, to promote the growth of branches and leaves. The Lignification of new branches and leaves after August is the key period of budding of rhododendron. Fertilizer mainly composed of phosphorus and combined with nitrogen and phosphorus should be applied 2 to 3 times, once every half a month. At this time, if there is no fertilization, or the lack of phosphate fertilizer or the use of high nitrogen fertilizer such as soybean juice, the cuckoo will only grow branches and leaves without pregnant buds. No fertilization is needed during winter dormancy. Before flowering, phosphorus was mainly applied, and the thin fertilizer combined with nitrogen and phosphorus was applied once or twice to make the flowers big and colorful. At this time, the concentration of fertilizer should be low, and too strong will cause the buds to scorch and fail to bloom.

Fifth, light. Rhododendron is a semi-shady plant, avoid the direct sun and dry muggy heat, so maintenance should be placed in a semi-shady ventilated place.

6. Pruning. Rhododendron plants are low, strong sprouting power, dense overlapping branches, more transverse branches, not conducive to ventilation and light, so attention should be paid to pruning. The pruning time should be after blooming in spring and in autumn and winter. Timely erase adventitious buds and remove too many buds. Especially after flowering, there will be a small number of withered and yellow branches and old leaves falling off. It is necessary to pick the residual flowers in time, trim the diseased branches, grow branches and disturb the tree shape, so as to improve the crown width and ventilation and light transmission conditions.