What to do when periwinkle leaves turn yellow? Causes and solutions for potted plants
Periwinkle (Catharanthus roseus) is best grown in fertile, well-drained soil. It is a light-loving plant and must have plenty of sunlight during the growing season. It prefers a warm, slightly dry, sunny environment. When fertilizing, you can apply a compound fertilizer and a liquid fertilizer alternately once every ten days. It dislikes wet conditions and is afraid of waterlogging, so the potting soil should not be watered too much. The plant itself is toxic, so it is relatively resistant to pests and diseases. Stem and leaf rot mainly occurs during the rainy season, so take care to prevent and control it.
During the growing season of potted periwinkle, insufficient fertilization, excessive watering or poor drainage will all cause the leaves to turn yellow. By addressing the above causes and promptly strengthening care, yellowing leaves can be avoided. What should you do when the leaves of potted periwinkle turn yellow?
1. Soil on the alkaline side
Periwinkle does not have very high soil requirements, but it dislikes alkaline soil. Growing periwinkle in alkaline soil will cause its leaves to turn yellow and prevent it from blooming.
Solution: Test the pH of the soil to be used. If the soil is on the alkaline side, it must be treated.
2. Poor soil aeration
Poor soil aeration is also a cause of yellowing periwinkle leaves. Many people choose soil for growing periwinkle that is highly sticky and poor in water permeability and aeration. This may not show any problems in the short term, but over time, soil with poor water permeability and aeration causes the lower roots of the periwinkle to have difficulty breathing, leading to frequent yellowing and dropping of leaves. Periwinkle requires a loose substrate with good aeration. If planted in sticky, slightly alkaline soil, the soil becomes compacted, causing poor root development, which affects the growth of the above-ground part and makes the leaves turn yellow.
Solution: Choose sandy soil with good drainage for planting, and also be careful not to water too much.
3. Insufficient light
Periwinkle likes warmth and a sunny environment. If a potted plant is placed in a shaded spot for a long time, the leaves will turn yellow due to insufficient light.
Solution: Periwinkle is a light-loving plant and must have plenty of sunlight during the growing season; then its leaves will be verdant and glossy and its flowers brightly colored. In daily care, it should be given appropriate light.
4. Overwatering
Periwinkle dislikes wet conditions and is afraid of waterlogging, so the potting soil should not be watered too much; otherwise it will affect root respiration, causing old leaves to turn yellow and new leaves to be pale yellow.
Solution: Strictly control watering, and it is better to keep it on the dry side. Pay attention to drainage during the rainy season.
5. Underwatering
Periwinkle cannot take too much water, but too little is also a problem. If you water too little or the water does not penetrate the soil thoroughly for a long time, the plant cannot absorb enough water; new leaves will wilt, while old leaves will turn yellow and drop off.
Solution: Pay attention to watering. You can water after the potting soil has dried out completely, and water thoroughly.
6. Overfertilizing
Many people who grow flowers at home often worry that insufficient fertilizer will lead to poor blooming, so they occasionally put a bit of fertilizer or something else into the potting soil, hoping the plant will absorb it and bloom more. In fact, too much or too concentrated fertilizer can burn the roots and damage the root system, leaving the whole periwinkle plant listless, growing slowly, blooming little, and with smaller petals.
Solution: For periwinkle, you can apply a compound fertilizer and a liquid fertilizer alternately once every ten days, and do not fertilize casually at other times.