Why Are the Leaves of the Azalea Turning Yellow? This Is How to Grow It Well

Azalea, also known as rhododendron, mountain azalea, mountain pomegranate, yingshanhong, zhaoshanhong, and Tang azalea, has many varieties, brilliant flower colors, and relatively large blooms. For most flower lovers it is not considered easy to grow, mainly because its habits are not well understood. During the care of the azalea, the question often arises: why are the leaves turning yellow? How can it be grown well?

I. Why are the leaves of the azalea turning yellow?

1. Watering

Overwatering: If the potting soil stays too wet for a long time, it causes a lack of oxygen in the soil, making some of the azalea's fibrous roots rot, which hinders the azalea's normal respiration and its absorption of water and nutrients, causing the azalea's leaves to turn yellow and drop. After the azalea is affected, the young leaves first turn pale yellow, and then the azalea's old leaves also gradually turn yellow. Watering should be controlled immediately, fertilizing should be paused, and the soil should be loosened frequently so that the soil is well aerated.

Underwatering: If the azalea misses watering or is watered with half-water (that is, wet on top and dry below) for a long time, nutrient absorption is affected, and the azalea's leaves are also prone to becoming dull and lusterless, wilting and drooping. In the azalea, the lower old leaves age first, and gradually dry up, turn yellow and drop from bottom to top. A small amount of water should be given along with misting, so that the azalea gradually recovers and then returns to normal watering.

2. Light

Too much light: In summer, if the azalea, which prefers cool conditions, is placed in a hot spot under direct strong sunlight, it easily causes the tips and edges of the azalea's young leaves to scorch, or the azalea's leaves to turn yellow and drop. It should be moved promptly to a well-ventilated, shady place.

Too little light: If the azalea, which likes sunlight, is kept for a long time in a shaded place or a spot with insufficient light, it will cause the azalea's branches and leaves to grow leggy, with thin and yellow leaves, and it will not bloom or will bloom very little. Take care to move the pot to a sunny spot.

3. Alkaline soil and water

Most areas in the north have relatively high salt and alkali content in the soil and water. The azalea is a flower that likes acidic soil, and because the soil lacks soluble iron and other elements that it can absorb, the azalea's leaves gradually turn yellow. When planting, choose acidic soil, and during the growing period often water with alum fertilizer water.

4. Improper temperature

If the room temperature in winter is too low, the azalea is prone to cold damage, which causes the azalea's leaves to turn yellow, and in severe cases to wither, turn yellow and die. If the room temperature is too high, the azalea's transpiration is excessive, and the roots cannot supply enough water and nutrients, which also makes the azalea's leaves turn yellow. Each year in late autumn, around mid-October, the azalea should be brought indoors for care. In winter, place the azalea in a spot with ample sunlight, and keep the indoor temperature at 5—10°C, but it must not be lower than 5°C, otherwise the azalea will stop growing or die.

5. Fertilizing

Too little fertilizer: If the azalea has not been given nitrogen fertilizer for a long time or has not been repotted or given fresh soil, the soil lacks nitrogen and other nutrient elements, causing the azalea's branches and leaves to become weak, with thin and yellow leaves. Repot promptly, replace with new loose and fertile potting soil, and gradually increase applications of dilute, well-rotted liquid fertilizer or compound flower fertilizer.

Too much fertilizer: If too much fertilizer is applied, the new leaves become thick and fleshy with many bumps and unevenness, and the old leaves dry at the tips, scorch yellow and drop. Fertilizing should be stopped immediately, watering increased so that the fertilizer flows out through the drainage holes at the bottom of the pot, or the plant should be repotted immediately, the soil ball rinsed with water, and then replanted in the pot.

I. How can the azalea grow well?

1. The azalea is a shade-loving plant, and direct sunlight is bad for its growth, so a shaded spot is best.

2. The azalea likes an environment with high air humidity. You can mist the leaves or spray the surrounding air to keep the surrounding air moist.

3. The azalea likes well-drained, acidic soil that is loose, fertile and rich in humus. An acidic sandy loam is suitable, and it should not become waterlogged.

4. Pruning notes: Pruning of branches is generally done in spring and autumn. Cut off crossing branches, overly dense branches, overlapping branches and diseased or weak branches, and promptly remove spent flowers. This increases ventilation and light penetration, and also benefits the plant's growth.

5. Notes on pot culture: Pot culture is a bit more troublesome. In mid-to-late April, move it out of the greenhouse, first placing it in a wind-sheltered, sunny spot; in summer provide shade, or place it under a tree in dappled shade, avoiding direct strong sunlight. The suitable growing temperature is 15-25°C, with a maximum temperature of 32°C. In late autumn, starting in mid-October, move it indoors, place it in a spot with ample sunlight in winter, and keep the room temperature at 5-10°C; the lowest temperature must not be below 5°C, otherwise growth stops.