Plants are pretty ornaments if there weren't numerous diseases. Yellow leaves show chlorosis, but how is it treated?
chlorosis
What is the disease?
Chlorosis is nicknamed jaundice, a name derived from yellow leaves. It is a deficiency that can occur in both ornamental and useful plants. The chlorophyll it contains, which should actually ensure a lush, green leaf, is not formed properly in the case of the disease.
Oleander with yellow leaves
impact
What effects does this have on the plant?
The green leaves are used by plants so that they can convert sunlight into energy. A plant suffers chlorosis, their ability to photosynthesize is disturbed. First, yellow leaves form, then they are shed. Fruits also gradually fall off until the plant finally stops growing altogether.
In the case of useful plants, the harvest suffers from the disease, and in the case of ornamental plants, the appearance is particularly affected. If you don't fight the disease, the affected plant will die within a few months to years. Plants of all kinds are affected, even coniferous trees or aquatic plants can become ill.
damage picture
How can chlorosis be diagnosed?
In order to be able to fight the disease, it must first be diagnosed. The first symptoms appear on young leaves, only later the old foliage is attacked. The one present in the leaves chlorophyll (Leaf Green) will gradually degrade until only yellow dye (carotenoids) is present. The foliage gradually turns yellow, sometimes the veins can still be seen in rich green. If you do not fight chlorosis at this time, the leaves will fall off and the plant will wither.
causes
What causes chlorosis?
The disease can occur for a variety of reasons.
These include:
- nutrient deficiency
- water stress
- over-fertilization
- Diseases
- compression
Rhododendron gets yellow leaves
Cause of nutrient deficiency
One of the most common causes is a nutrient deficiency. In most cases there is a lack of iron, but sometimes nitrate or magnesium are also affected. If the soil contains too few nutrients, the deficiency symptom develops with yellow leaves.
Subtype calcareous chlorosis:
If iron deficiency is to blame for the change, one speaks of calcification. It's not the lack of iron that's to blame, but a too high pH value in the soil. It is mostly potted and indoor plants that suffer from this form of chlorosis. Plants such as hydrangeas or rhododendrons are particularly known to be sensitive to lime.
High pH
What causes the high pH value?
If the affected plants are watered with heavily calcified water, the pH value increases. The plant is then no longer able to absorb the iron that is actually contained in the substrate. The result is an iron deficiency.
Combating high pH
In order to lower an excessive pH value in the soil, an incorporation of acidic peat or rhododendron soil is necessary. In addition, you can cover the soil with needle litter and in this way increase the acidity in the soil. An iron fertilizer may also be suitable to bring the plants back into shape. However, it is recommended that you spray the fertilizer onto the foliage so that the nutrients can be easily absorbed.
Rapid lowering of pH:
- Mix soil with rhododendron or peat soil
- Use needle litter to cover the floor
- Spray plants with iron fertilizer
water sprayer
To prevent further calcification of the soil, you should use rainwater or tap water without lime in the future.
Subtype growth chlorosis:
In addition to the classic nutrient deficiency, there is what is known as growth chlorosis. Although there are sufficient nutrients in the soil, deficiency symptoms occur. The reason for this is a rapid, rapid growth of the leaves. The plant cannot absorb as much iron as it needs and as a result it cannot produce enough chlorophyll.
Combat growth chlorosis
To combat growth chlorosis, you should encourage the plant to absorb iron. For this, a sprayable iron fertilizer is suitable, which is applied directly to the leaves. It also helps if you add compost to the soil. If you may have applied bark mulch and not previously spread horn shavings, this may be the cause of the yellowing of the leaves. You can quickly remedy this by removing the bark mulch.
water stress
Water stress as a trigger
The disease can be the result of so-called water stress to which the plant is exposed. Water stress refers to waterlogging and water shortages. If there is a lack of water, the available nutrients cannot be transported to the leaves and the plant stops photosynthesis. Waterlogging, on the other hand, leads to root rot and parts of the root tips die off. However, these are necessary so that enough nutrients can be absorbed.
Combating water stress chlorosis
When water stress is the cause of chlorosis, changing watering habits is the best treatment. The first step is to find out how much water your plant actually needs. If there is waterlogging, you should water less and put drainage in the soil. If there is not enough water, you must shorten the watering cycles and water more frequently.
Tree friend with yellow leaf
over-fertilization
Over-fertilization as a trigger for chlorosis
Fertilizing can make sense, but sometimes there is an oversupply of fertilizers. If there are too many nutrients in the soil, the water intake of the plants will be drastically reduced.
Important tips for correct fertilization and prevention of chlorosis:
- only use mineral fertilizers in exceptional cases
- resort to organic fertilizers
- excess fertilizer can be rinsed off with water
- Changing the substrate can reduce the amount of fertilizer
Diseases
Diseases that cause chlorosis
Yellow leaves can form on plants due to bacteria, viruses and fungi. You can recognize a disease as the trigger when the leaf suddenly turns red after turning yellow. This red pigment is created as a result of a natural defense mechanism, the plant protects itself against environmental stress and infections.
Compacted substrate
Chlorosis by compression
A very compacted plant substrate can also be the cause of developing chlorosis. When the roots are no longer able to absorb nutrients from the soil, the leaves turn yellow.
Sufficient nutrients are available, but the plant still suffers from a deficiency. The carbon dioxide content increases in the soil, which is why there is a lack of oxygen.
Aeonium undulatum, thick-leafed plant, with yellow leaves
combat
combating chlorosis
The progression of chlorosis is slow and lengthy. The fight works just as well in the long term. There are hardly any immediate measures, instead the living space often has to be changed.
The following measures are helpful:
- transplant if the substrate is wrong
- loosen the ground
- replacement of the irrigation water
- as emergency aid iron fertilizer