Dealing with plants’ yellow leaves
Yellow leaves on your plants is a very common problem in the Antelope Valley.
Yellow or pale green leaves can be a symptom of several different problems with your plant. So, having a plant with yellow leaves is not a good symptom by itself, you need to investigate further to hopefully identify the problem.
The first step to determine the problem is to determine the location of the yellow leaves on your plant. There are basically three locations that yellow leaves are found on the plant.
The first is older leaves. These are the leaves that are located on the oldest parts of the plant or the leaves that have been on the plant for the longest time. The second location is younger leaves. These are the newest leaves on the plant. The last location is a generalized area of the plant, such as one side of the plant, or an area on one side of the plant.
If the older leaves are the ones turning pale green and finally yellow, it can be one of several problems. It usually means too much water. Check the soil and see if it is wet, and allow the soil to dry before watering again. Your soil could be dry, but the plant was over-watered several days or weeks ago. This rotted the roots and they take a few weeks to show the yellow leaves.
It could also mean that your plant has a nitrogen deficiency. Our soils are low in nitrogen, and I find most people never fertilize their plants correctly. If you have been watering your plants heavily, then the water can leach the nitrogen out of the soil.
If your plant does not receive enough light, the older leaves may turn yellow. Root rots and nematodes can also cause older leaves to turn yellow. Last, leaves do not live forever; it may just be time for the leaves to die.
You will also need to determine if the leaf is solid yellow or does the leaves have yellow splotches or is the leaf primarily yellow between the veins in the leaves. If the older leaves have yellow splotching, it is probably a virus; there are no cures for viruses. If the leaves are green with yellow between veins, you have the classic symptom of a magnesium deficiency.
If the younger leaves are solid yellow, it could mean that the soil pH is too high, which in the Antelope Valley is a common problem, especially on acid loving plants like gardenias and camellias. Related to having a high pH, yellow on younger leaves could mean that your soil my have a high salinity level. High salinity means too much salt in your soil. This does not mean table salt, but probably too much fertilizer, which is also a salt.
Yellow young leaves can also mean that your plant may have a sulfur deficiency. All of these are common problems in the Antelope Valley.
If the younger leaves have yellow splotches, it is again probably a virus, and there still is no cures for viruses. If the leaves are green with yellow between veins, you have the classic symptom of an iron, manganese or zinc deficiency.
If the yellow leaves are in a generalized area, it could be sunburn (especially reflecting off windows and cars), or just heat. It could be a dog spot from male dogs, lifting their legs on your plants. It could be a chemical burn from pesticides, or fertilizers spilled on the plant. I have even seen yellow leaves where someone poured hot water on a plant.
Hopefully I have narrowed down the problems. Now you need to continue to investigate the conditions and see if you can find your answer to yellow leaves.