Olive trees are actually robust and easy-care plants. However, the trees in this country struggle with a lack of light and well-intentioned watering, especially in winter. These and other causes cause the leaves of the olive tree to turn yellow. The measures that will make the tree fit are usually simple, but go hand in hand with a change in care.
Yellow leaves on the olive tree
If the leaves of the olive tree, botanically Olea europaea, turn yellow, this is a serious alarm signal that the tree is not feeling well. Therefore, you should act immediately to save the tree. There are many reasons why leaves turn yellow. They are related to the German climate and/or care mistakes. The most common causes of yellow leaves are:
- age of the leaves
- lack of light
- wetness
- dryness
- nutrient deficiency
- fungal infections
- container, sun exposure
age of the leaves
Olive tree leaves do not live forever. Their life span is between two and three years. When this is over, the leaves fall off. Before that, however, the old leaves turn yellow. In older or old olive trees, the proportion of old leaves is around 10 percent. On the olive tree, they do not sit on the tips of the shoots, but further down on the branch. The discoloration itself is flat, i.e. without a pattern. There is no "solution" here, as it is a natural process.
lack of light
As a Mediterranean plant, the olive tree loves the sun, even 12 hours a day. This love of the sun is a characteristic that olive trees cultivated in Germany also have. However, the German climate does not meet these requirements.
In summer, when the olive tree has a sunny spot on the south-facing balcony, the hours of sunshine meet the requirements. However, if the olive tree comes into the winter quarters after the outdoor season, the leaves turn yellow because it is too dark for the tree there and fall off. This problem increases the warmer the winter quarters are.
The solution to this problem is simple if you have enough space in the winter quarters. Simply place the olive tree in a place where it gets more light or sun. A sunny location with temperatures between five and ten degrees Celsius is ideal, such as a bright stairwell. If the winter quarters are warmer, the lack of light must be compensated for with a plant lamp. A lighting duration of eight to ten hours per day is ideal here.
tip: For a cool winter, the light should be at least 2,000 lux per square meter.
If the balcony or terrace is protected, you can also overwinter Olea europaea outside if you pack it up well from top to bottom, because the trees tolerate temperatures of up to 15 °C, but not for weeks. It is important that the crown is loosely wrapped in a translucent material. In addition, you must also cover the earth. A wooden board or a styrofoam plate helps against cold feet.
wetness
Yellow leaves on the olive tree due to wetness usually appear in late winter or early spring. The reason for this is that the olive tree has been watered too much during the winter. Another cause is too much rain in spring. If the temperatures allow it, the tree can move back outside in the spring. However, if spring rains, the water in the bucket does not drain off quickly enough. Since the sun is still too weak, the water cannot evaporate quickly enough, and the foliage turns yellow.
In the first step, Olea europaea must be drained, i.e. repotted. If the bucket is not completely rooted, you can use it again. If the tree is to be placed in a new pot, it should have a maximum diameter of four to six centimeters larger than the old one. Regardless, you should check that the drain holes are large enough for water to drain properly. When repotting, proceed as follows:
- Lift the olive tree out of the bucket
- Shake off soil and loosen roots
- Cut off soggy and/or rotten roots
- Rinse roots and let dry
- Provide the bottom of the bucket with a drainage layer of broken pottery, gravel, grit or expanded clay pebbles
- if necessary, place an air- and water-permeable fleece over the drainage layer (prevents clogging)
- Fill buckets with fresh, dry soil
- Plant olive tree
- fill voids
- do not water
So that the tree can regenerate, it is placed in a partially shaded location for about a week after repotting. Since too much moisture was the reason for repotting, the tree is not watered during this time. Then he can move to a sunny and rain-protected place.
The second step is species-appropriate watering. If there is no moisture meter, only water the tree when the substrate has dried well (thumb test). Water the tree slowly. The water requirement is covered when the first drops run down from the bucket.
tip: If you are unsure whether you should water the olive tree or not, it is better not to water it. Because the tree tolerates drought better than too much moisture.
dryness
Although Olea europaea prefers drought, a lack of water can also harm it. The olive tree shows this through yellow leaves. This damage often occurs in summer because the tree is not watered enough to avoid waterlogging. To get to the bottom of the cause, you need to lift the tree out of the pot and examine the root ball.
If the roots are completely dried out, then they have to be immersed:
Fill bucket or container of appropriate size with water
Dip the root ball in it until no more air bubbles can be seen
tip: Once the olive tree has been planted, water it with the garden hose for at least ten minutes.
So that the tree does not suffer from drought stress in the future, water it promptly when the soil has dried.
nutrient deficiency
If the olive tree does not get enough nutrients, the leaves turn yellow. However, this only applies to olive trees that are cultivated in tubs. Planted trees receive sufficient nutrients from the soil. When investigating the cause, you should pay attention to the following:
- flat, yellow discoloration on leaves
- no fertilizer lately
- no repotting in recent years (substrate consumption)
Since the tree suffers from a lack of nitrogen, it must be fertilized. In order to take care of him properly, you should give him a special fertilizer for Mediterranean plants. But don't give it too much fertilizer, even if it's well intentioned, because over-fertilizing isn't good for the tree either. It is best to follow the packaging instructions and fertilize the olive tree regularly until it moves to winter quarters. Fertilizer is not used in winter, but only again in the coming spring.
fungal infections
Fungal infections occur more frequently when Olea europaea suffers from moisture. Quick help is needed here. The most common fungal infection is eye spot disease (Spilocaea oleaginea). You acknowledge the infestation:
- round, light spots with a dark edge
- yellowed foliage
If the fungus has infected the tree, take the following measures immediately:
- pluck off infected leaves
- collect fallen ones
- Dispose of infected plant parts (including those from the ground) in the household waste
- Treat fungus with fungicides
The second fungus that mainly attacks young olive trees is Mycocentrospora cladosporioides. Yellow leaves also appear on the olive tree with this fungal infection. If less than 30 percent of the foliage is affected, then plucking it off should rid the tree of the fungus. If the infestation is severe, a fungicide must be used to save the tree.
bucket
If the causes mentioned for yellow leaves on the olive tree can be ruled out, then you should take a closer look at the bucket. If it is black or very dark, then the roots in the bucket are too hot and they die, which in turn is reflected in yellow leaves. A quick help for the tree is to wrap the bucket or planter in a light-colored fabric. The next time you repot it, it goes into a bright bucket.
If the sunlight falls through glass on the tree in summer, the leaves can burn due to the refraction. They turn yellow, brown quickly and fall off. In this case, only a change of location will help.
