There are many reasons for the yellow leaves of Rhododendron: there are watering problems, fertilization problems, temperature problems, soil problems, etc. Let's take a look at the cause analysis and solutions of the yellow leaves of Rhododendron arranged by Xiaobian. For example, is there one of your Rhododendron?
Cause analysis and solution of Rhododendron Leaf Yellowing: 1. Excessive watering. 2
The basin soil is too wet for a long time, resulting in hypoxia in the soil, causing some fibrous roots to rot, hindering normal respiration and water and nutrient absorption, causing leaves to turn yellow and fall off. After the damage, the young leaves first turn pale yellow, and then the old leaves turn yellow gradually. Watering should be controlled immediately, fertilization should be suspended, and the soil should be loosened frequently to make the soil ventilated well.
2. Drought dehydration
Missing water for flower cultivation or long-term half waist water (i.e. wet up and dry down) will not only affect nutrient absorption, but also easily cause dull leaf color, leaf wilting and drooping. First, the lower old leaves aged and gradually withered and fell off from bottom to top. At this time, it is necessary to water a small amount and spray water to make it recover gradually, and then turn to normal watering,
3. Long term fertilizer removal
For a long time, no ammonia fertilizer was applied or the pot and soil were not changed, and there was a lack of nitrogen and other nutrient elements in the soil, resulting in thin branches and leaves and thin and yellow leaves. Pour the pot in time, replace with new loose and fertile culture soil, and gradually apply thin rotten liquid fertilizer or compound flower fertilizer.
4. Excessive fertilization
Excessive fertilization will cause new leaves to be thick and uneven, and the dry tips of old leaves will be scorched and fall off. Fertilization should be stopped immediately, and the amount of watering should be increased to make the fertilizer flow out of the drainage hole at the bottom of the basin, or pour the basin immediately, wash the soil lump with water, and then plant it again in the basin.
5. Hot and high temperature
In summer, if cool flowers (such as Cyclamen, upside down Golden Bell and four seasons Begonia) are placed at a high temperature and directly exposed to strong light, it is very easy to cause the tip and edge of young leaves to scorch or yellow leaves to fall off. Move to a well ventilated and cool place in time.
6. Excessive shade
If sunshine loving flowers are placed in shade or places with insufficient light for a long time, it will lead to excessive growth of branches and leaves, thin and yellow leaves, no or few flowers. Be careful to move the flowerpot to the sunny place.
7. Alkaline water and soil
The soil and water in most areas of the North contain a lot of salt and alkali. Plants like acidic soil flowers, such as azalea, camellia, Michelia, gardenia, orchid, brandy, osmanthus, etc. because the soil lacks soluble iron and other elements that can be absorbed by it, the leaves will gradually turn yellow. Acid soil shall be selected for planting, and alum fertilizer and water shall be often poured during growth.
8. Airtight
If too much nitrogen fertilizer is applied, the branches and leaves will grow luxuriantly. In addition, if they are not trimmed for a long time, the light of the inner chamber branches and leaves will be insufficient, which is easy to cause the leaves to turn yellow and fall off. Fertilization should be reasonable and pruning should be strengthened to make it ventilated and transparent.
9. Air drying
When the indoor air is too dry, some flowers that like humid environment, such as Chlorophytum and orchid, often have dry leaf tips or scorched leaf edges. Attention shall be paid to increasing air humidity by spraying water and covering with plastic film cover,
10. Improper temperature
In winter, the room temperature is too low. Flowers that like high temperature are often vulnerable to cold damage, resulting in yellowing of leaves and death in serious cases. If the room temperature is too high, the plant transpiration is too high, the root water and nutrients are in short supply, and the leaves will turn yellow. Please pay attention to adjust the room temperature in time.
11. Soil acid
The red loam in South China is acidic, and magnesium is easy to be lost. Planting flowers and trees that are alkali resistant or like slightly sealed soil, such as oleander, boxwood and winter jasmine, is often prone to chlorosis and yellowing between the veins of old leaves. Calcium magnesium phosphate fertilizer can be applied or magnesium sulfate solution can be sprayed.
13. Diseases and insect pests
Leaf spot disease caused by fungi and other pathogens is easy to cause local necrosis of leaves, yellow spots or patches, and the whole leaf withers and falls off in severe cases. After being infected by mosaic virus, yellow and green mottle appears on the leaves; If damaged by scale insects and red spiders, the leaves will become partially yellow and withered, and even the whole leaf will wither and fall off. Spraying shall be carried out in time.
13. Strong stimulation
Excessive pesticide concentration in pest control, or pollution by toxic gases in the atmosphere, or sudden watering of cold water when the temperature is high, are easy to cause local yellowing and scorching of leaf tip or leaf surface, or even death of the whole plant. Therefore, we should pay attention to the rational use of pesticides and try to eliminate air pollution sources. Avoid watering flowers with cold water around noon in midsummer. Finally, it should also be mentioned that the yellow leaves of potted flowers are sometimes caused by one reason, but they are often caused by a variety of factors. Correct diagnosis should be made before the remedy can be applied to the case.
Beautiful Rhododendron generally speaking, Rhododendron likes acidic soil and does not grow well in calcareous soil; Rhododendron likes cool, humid and ventilated semi shade environment. It is afraid of both hot and cold. The suitable temperature for growth is 12 ℃ to 25 ℃, and the temperature in summer exceeds 35 ℃, the new shoots and leaves grow slowly and are in semi dormant state. Sunscreen and shade in summer and keep warm and cold in winter. Avoid exposure to the sun. It is suitable to grow under the scattered light with low light intensity. If the light is too strong, the young leaves are easy to be burned, and the new leaves and old leaves are scorched. In serious cases, it will lead to plant death. In winter, measures should be taken to protect Rhododendron from cold in order to ensure its safe wintering. Among the ornamental rhododendrons, the West Rhododendron has the weakest cold resistance, and is prone to freezing injury when the temperature drops below 0 ℃. Therefore, we should pay attention to the above 13 sins when breeding Azalea.