Reasons for the Dry and Brittle Leaves of Gardenias
Let me share with you some small experiences in plant cultivation regarding the reasons for the dry and brittle leaves of gardenias and the correct methods of winter care. Next, the editor will introduce them.
When potted gardenias show signs of withered leaves, chlorosis is the most common disease causing yellowing of the leaves. The main causes are excessive dryness of the soil, root problems, high alkalinity of the soil, and insufficient soil nutrients. Withering leaves of gardenias need to be taken very seriously, first observing their growing environment and plant condition, determining the cause, and taking appropriate measures. Let's understand the reasons for the withered leaves of potted gardenias and how to deal with them.
I. Excessive or Insufficient Soil Moisture
Gardenias require plenty of water, but the soil should not be overly moist, as this will turn the leaves yellow, showing old leaves yellow and leaf veins green. While applying compound fertilizer to improve the growing substrate, move the potted plant to a ventilated area to dry, and water after loosening the soil, mastering the watering frequency. It is also essential to ensure good drainage and aeration of the potting soil, and if the existing potting soil does not meet these requirements, consider repotting.
II. Excessive Dryness of Soil
It may also be due to the soil being too dry, especially in northern winters. The measure is to replace the pot with a larger saucer, add water to the saucer to let the potting soil absorb it, and place it on a north-facing window sill with scattered light until the plant recovers. If the old leaves turn from yellow to dry, the reason might be dry air, in which case, increase the humidity or spray water around the plant or lay a wet towel on the ground.
III. High Soil Alkalinity
If it is not caused by soil moisture, consider whether the soil alkalinity is too high. The best soil for growing potted gardenias is breathable, well-drained, and fertile. Gardenias prefer acidic soil with a pH between 5.0 and 6.5. If the soil pH is not suitable, the plant may not effectively absorb the required soil chemical elements, such as iron, nitrogen, magnesium, and zinc, leading to mineral element deficiencies, such as the commonly deficient magnesium and iron, which can cause chlorosis and yellowing of the leaves.
When deficient in magnesium, the base and tip of the leaves remain green, and the base may turn dark green. You can apply a dose of phosphates, such as a 1% magnesium sulfate solution.
Lack of iron leaves the base and veins green, and when the weather gets cold, making it more difficult for the plant to absorb soil nutrients, it can cause chlorosis. It is usually advisable to treat in spring, using a dilute solution of a sulfur-free agent to lower soil alkalinity, such as 0.2% ferrous sulfate solution.
IV. Poor Adaptation of the Plant
For plants in the acclimatization period, if the leaves first turn yellow and then the edges burn, move them to a position without direct sunlight to recover, ensuring that the soil moisture and air humidity are suitable. Avoid applying fertilizer and ferrous sulfate, and do not remove the yellow leaves.
V. Insufficient or Improper Care
1. Fertilization
A short-term solution to plant chlorosis is to directly supplement the deficient elements into the soil, but this is only temporarily effective. Long-term, it is necessary to fertilize regularly and in the right amount. Apply fertilizer directly to the soil, away from the plant's roots, to reduce direct contact with the fertilizer and avoid fertilizer burn, which is another way to reduce yellow leaves.
2. Temperature
The optimal growing temperature for gardenias is between 16 and 18 degrees Celsius, and they require temperatures between 5 and 10℃ to overwinter. Below -10℃, they can easily suffer from frost damage, causing the leaves to turn yellow.
3. Light
Gardenias are sensitive to direct sunlight and should receive about 60% full sunlight daily. Insufficient lighting hinders photosynthesis.
4. Diseases and Pests
Plants with chlorosis and leaf spot disease will have leaves that turn yellow and gradually wither, while pests can also harm plant health, causing leaves to become wilted and diseased leaves to turn yellow. Pests include moths, scale insects, and whiteflies. It is essential to control diseases and pests promptly when discovered and to take preventive measures and strengthen plant care to enhance disease resistance.
The above are the reasons for the dry and brittle leaves of gardenias and the correct methods for their winter care. I hope this information can be helpful to you in your daily life!