Causes of Yellowing Osmanthus Leaves and Solutions

No matter which city, osmanthus is an important marker of autumn's character. Whenever this time comes, the wind brushes the osmanthus lightly, tree shadows grow sparse, and a subtle fragrance surges. Some flower lovers also grow osmanthus as potted plants at home, which not only decorates the environment but also lets them smell the fragrance of osmanthus at all times. But in the specific cultivation process, osmanthus leaves often show a phenomenon of yellowing. What is the cause of this? What are the solutions?

I. What causes osmanthus leaves to turn yellow?

1. Overwatering causes osmanthus tree leaves to turn yellow (water yellowing)

If suffering from waterlogging damage, the root system turns black and rots; the leaves first have scorched leaf tips, then the whole leaf turns yellow, withers and falls off, ultimately leading to the death of the entire plant.

2. Root rot causes osmanthus tree leaves to turn yellow

The affected parts of osmanthus root rot appear water-soaked; after the lesions gradually expand, they cause the plant to grow weak or even die. This osmanthus disease often occurs in the rainy seasons of summer and autumn. The cause is that the soil is too wet, which weakens the resistance of the root system, and pathogens take the opportunity to invade.

3. Long-term water shortage causes osmanthus tree leaves to turn yellow (drought yellowing)

Watering too little, or long-term watering only halfway or missing waterings, makes the leaf moisture evaporation greater than absorption, causing water supply to fall short of demand, which can also cause leaves to turn yellow. “Drought yellowing” means the lower leaves gradually turn yellow, scorch and fall off upward, and in severe cases the petioles droop and appear wilted.

4. Long-term lack of fertilizer causes osmanthus tree leaves to turn yellow (fertilizer-deficiency yellowing)

Insufficient fertilization, especially long-term failure to apply nitrogen fertilizer or change potting soil, leads to a lack of nitrogen nutrition in the soil, causing branches and leaves to become thin and weak, and leaves to be thin and yellow.

5. Exposure to full sun causes osmanthus tree leaves to turn yellow

In summer, cultivating it in a place with direct strong light can easily cause young leaf buds or leaf margins to scorch or the entire leaf to turn yellow.

6. Overfertilization of osmanthus trees causes leaves to turn yellow (fertilizer yellowing)

Too much fertilizer, especially too much nitrogen fertilizer with a lack of phosphorus and potassium fertilizer, easily causes leaves to turn yellow, shown as new leaves being thick and mostly uneven on the surface, while old leaves gradually turn yellow and fall off; in severe cases the leaf tips dry up, or even the entire leaf becomes scorched yellow.

7. Insufficient sunlight causes osmanthus tree leaves to turn yellow (light-deficiency yellowing)

If it is kept for a long time indoors in a place with insufficient light, growth becomes weak, leaves become thin and yellow, and it does not bloom or blooms very little.

II. Solutions for yellowing osmanthus leaves

1. Solution for overwatering: In severe cases, the entire root ball needs to be removed from the pot and placed in a pile of dry soil so that moisture can quickly seep out; after the drooping branches and leaves recover, replant it in the pot.

2. Solution for osmanthus tree leaf yellowing caused by root rot: In early spring, a small amount of sulfur powder can be scattered around the osmanthus to kill pathogens in the root zone. In winter, the trunk can be whitewashed with a whitewash mixture made of 25 jin of quicklime, 3 jin of table salt, 0.5 jin of vegetable oil, 1 jin of sulfur powder, and 100 jin of water. In rainy seasons, strengthen ditch clearing and drainage. After disease spots appear on the osmanthus trunk, scrape them clean and apply asomate kerosene preparation, and at the same time water the roots with 500 times dexon. Diseased and dead plants should be dug out and burned promptly, and the soil at the original planting spot should be disinfected by watering with quicklime water to prevent the spread of pathogens.

3. Solution for long-term water shortage causing osmanthus tree leaves to turn yellow: After discovery, immediately move the flowerpot to a shady place, spray some water on the leaf surface, and water a small amount. Later, as the stems and leaves gradually recover their uprightness, gradually increase the amount of watering. If too much water is suddenly given at this time, it may cause plasmolysis, damage the protoplasm, and cause the flower to die.

4. Solution for fertilizer-deficiency yellowing: Promptly repot, take the plant out, replace it with a pot one size larger, fill it with new loose and fertile growing soil, and replant it properly. After watering thoroughly, place it in partial light to recover. After it resumes growth, apply dilute liquid fertilizer or compound chemical fertilizer.

5. Solution for osmanthus tree leaf yellowing caused by exposure to full sun: After discovery, immediately move it to a cool place with good ventilation for cultivation. If the temperature rises or the environment is dry, try to use shading and misting to improve environmental humidity. Generally, if the tips of old leaves are dry, it will improve as long as humidity is increased above 60%.

6. Solution for fertilizer yellowing: In this situation, fertilization should be stopped immediately and watering increased so that fertilizer flows out through the drainage holes, or immediately repot, remove part of the old soil, wash and rinse the root ball with water, replace part of it with new growing soil, and replant the plant in the pot.

7. Solution for light-deficiency yellowing: Arrange appropriately the degree and duration of light exposure for osmanthus. When cultivating this type of flower, it usually needs to be placed outdoors in a sunny place or a semi-light place, and after blooming it can be moved indoors for viewing.