Why Catharanthus roseus Leaves Turn Yellow and How to Fix It

When people first see Catharanthus roseus, they will surely think of Changchun City in China, but in fact this flower has nothing to do with Changchun City. In China, Catharanthus roseus is mainly cultivated in areas south of the Yangtze River, and its cultivation history in China is not that long either. Because this flower has a very long blooming period, and with proper care it can bloom almost all year round, it is a relatively common flower in our daily lives. However, during cultivation we often find that this flower develops yellow leaves. What should we do then? Below, Qinnong Web will introduce the reasons that cause the leaves of this flower to turn yellow, as well as the solutions after the leaves turn yellow.

1. Soil on the alkaline side

Catharanthus roseus can grow well in ordinary soil, except for saline-alkaline land. Catharanthus roseus is not strict about soil requirements, and soil that is well ventilated, fertile and has good drainage is suitable. If the soil is on the alkaline side, it will cause poor growth of Catharanthus roseus, causing yellow leaves and no flowering.

Solution:

Before planting, test the pH of the planting soil. If the soil is on the alkaline side, it must be treated. You can buy acidic soil directly at a flower shop, or add ferrous sulfate solution to the soil, which can both acidify the soil and increase its fertility.

2. Poor soil air permeability

Poor soil air permeability is also a cause of yellow leaves in Catharanthus roseus. The soil many people use for planting flowers is quite sticky and has poor water permeability. This kind of soil may not show any problems in the short term, but over time, the poor water and air permeability of the soil causes poor respiration of the lower roots of Catharanthus roseus, leading to frequent yellow leaves and leaf drop.

Solution:

There must be some care in choosing soil. As introduced above, soil that is well ventilated, fertile and has good drainage is suitable. When planting, choose sandy soil with good drainage performance, and also be careful not to water too much.

3. Overwatering

Catharanthus roseus dislikes moisture and fears waterlogging, so the pot soil should not be watered too much, otherwise it will affect root respiration and cause old leaves to turn yellow and new leaves to become pale yellow.

Solution:

Catharanthus roseus originated in tropical regions. During cultivation, watering must be strictly controlled, and it is better to keep it dry. In the rainy season, pay attention to drainage.

4. Too little watering

If overwatering is not okay, then can you water a little less? The answer is also no! If you water too little or the water does not penetrate the soil thoroughly for a long time, the plant cannot absorb enough water, the new leaves will wilt, and the old leaves will turn yellow and fall off.

Solution: During cultivation, pay attention to observing the plant's growth after watering, find the most suitable amount of water for growth, and when watering, implement the principle of “do not water until dry, and when watering, water thoroughly”.

5. Overfertilizing

Many beginners always worry when growing flowers that the flowers' nutrition cannot keep up, so they often fertilize the flowers. In fact, fertilizing can indeed make the flowers bloom more and more beautifully, but if it is too frequent, it will have the opposite effect. If fertilized frequently, Catharanthus roseus finds it very hard to absorb it all. The fertilizer remains in the soil and stays around the roots, causing the whole Catharanthus roseus plant to become listless, grow slowly, bloom less, and have smaller petals.

Solution:

Catharanthus roseus can be fertilized by alternating a compound fertilizer and a liquid fertilizer, and at other times do not fertilize casually. Water the day after fertilizing to promote nutrient absorption.

The above are the solutions introduced by Qinnong Web for dealing with yellow leaves on Catharanthus roseus. Qinnong Web would also like to remind everyone here that the whole plant of Catharanthus roseus is toxic, but after extraction, Catharanthus roseus is also a cancer treatment medicine, so whether you grow it yourself or see it by the roadside, do not eat it casually.