Suddenly the ornamental oleander has yellow leaves and it is completely unclear why this is so. The fact is, however, that plants often react to certain circumstances with yellow leaves. If the gardener is aware of these circumstances, he can react to them and counteract them with the appropriate care. There are many different factors why an oleander reacts with yellow leaves, because the plant has some special features when it comes to growth and care.
causes
cause determination
If the decorative plant suddenly shows yellow leaves, then something is wrong with the care or the location. Because the oleander is usually evergreen and rarely loses its lush green leaves, but it can happen from time to time that they turn yellow. Nevertheless, you shouldn't get into a hectic rush, the causes can be checked at your leisure and processed using a checklist.
The following factors should be checked:
- the location is too dark
- the oleander got frost
- a heat wave is currently in progress
- regular fertilizing was forgotten
- the plant was attacked by pests
- the yellow leaves are more than two years old
If one or more of the care mistakes or points apply, then it is quite normal for the leaves to drop. Because if the oleander gets too little light, nutrients or water, then it has to protect itself. In order to maintain a supply, it sheds the leaves that have already turned yellow due to the lack.
nutrient
nutrients help
Oleander is often cultivated as a container plant in the local latitudes, as it is only partially hardy and can therefore be moved to a sheltered location more easily in winter. Therefore, oleander plants in particular that have been cultivated in a pot need more fertilizer. If the Mediterranean plant does not receive enough nutrients, the leaves can turn yellow. But an oversupply is also possible here, to which the oleander reacts quickly. As a rule, however, the yellow leaves do not fall off, but remain hanging. This shows that the plant is suffering from an undersupply or oversupply of nutrients. Therefore, when fertilizing the plants used in the bed, the following should be observed in order to avoid yellow leaves.
- Oleander requires magnesium, iron and zinc
- fertilize in the tub every one to two weeks
- use special liquid fertilizer for oleanders
- do not use commercially available potting soil for the tubs
- the nutrients in this do not benefit the oleander
- better mix garden soil with clay
- Use long-term fertilizer for plants cultivated in beds
- only fertilize between May and August
If the oleander gets too many nutrients, this can also be a reason for the leaves to turn yellow. Because the plant is very sensitive. Therefore, you should always pay attention to the right mixture and proceed exactly according to the manufacturer's instructions for the fertilizer used. Unfortunately, giving this plant too much or too little can have ugly consequences. However, fertilizers specifically for oleanders are already commercially available, and these should also be used if necessary.
pour
Oleanders are originally native to the Mediterranean countries and are therefore used to high temperatures. Nevertheless, as a Mediterranean plant, it is one of those plants that have no problem with being wet for a long time. Originally and in the wild, the plants grow in river valleys. There is always a certain amount of soil moisture in the bank area. But that also means that the oleander does not want drought. If it is too dry, yellow leaves will quickly form. Therefore, the following points should always be observed when casting.
- Water daily when it is very hot
- in the early morning or late evening hours
- not on the leaves
- always from below to the roots
- water when the water in the saucer has evaporated
Of course, the plant should not be washed in so that the water is still above the ground and can be seen. Because even if the plant likes it moist, it is not an aquatic plant. It is therefore advisable to always water so much that part of the water remains in the saucer, but the soil above remains only slightly moist to dry.
decrepitude
It is quite common on an evergreen plant for old leaves to turn yellow and shed. This is the only way new, young leaves can grow again. Because even if the oleander is an evergreen plant, this does not mean that the individual leaves live forever and remain on the plant. It is common for the oleander to shed its leaves after two to four years. This means that all leaves older than two years will turn yellow and fall off in the near future. If there are only a few specimens, this is usually due to the age of the leaves. In this case, no additional care is required. However, the following can be done to keep the shrub ornamental.
- oldest leaves grow below
- if these are thrown off, nothing new grows back
- this can lead to baldness
- stop balding through rejuvenation cuts
- alternatively cultivate as a standard
Diseases
diseases and pests
The oleander can also suffer from various diseases and pests if it gets yellow leaves. However, diseases are quickly recognized by the fact that not an entire leaf but only parts or points on the leaf turn yellow. In such cases, it is usually fungal diseases or oleander canker caused by bacteria. In these cases, action must be taken quickly to prevent the disease from spreading.
- remove all affected leaves
- also cut off all affected shoots
- don't put it in the compost
- dispose of in household waste
- use fungicides to combat fungal diseases
- Treat the plant and adjacent plants as a whole
- Oleander cancer usually occurs in the winter quarters
- remove affected areas
- there is no remedy against bacterial contamination
- strengthen the plant in such a case
Scale insects in particular like to make themselves at home on the oleander plant. However, these can be easily driven away with an insecticide. Even in such cases, when the plants are attacked by pests and get yellow leaves as a result, they should be strengthened overall. These include, above all, brightness and warmth, sufficient water and not too many nutrients.
hibernation bug
Yellow leaves on the actually evergreen oleander can also occur with the wrong overwintering. The plant, which is only conditionally hardy, must be protected from frost and cold water in the local latitudes. But not every location is suitable in winter and can also cause yellow leaves, which is usually completely normal if there are only a few yellow leaves. Because the oleander separates from excess leaves during the resting phase. In this way, he does not have to supply them additionally in winter, especially when the winter location is not optimal. The following should be observed when overwintering Mediterranean plants.
- a bright, moderately cool location is ideal
- the supply must also be available in winter
- moderate watering is mandatory
- be sure to protect from frost
- do not fertilize in winter
Oleanders are often described as slightly frost hardy, but this is usually not the case. Therefore, he should also move to a frost-free winter quarters and not stay outside. Otherwise, only a radical pruning usually helps. If the first yellow leaves appear on an oleander that is still outside at the beginning of winter, it should be brought inside and protected as quickly as possible.
location
Only when the ideal location has been chosen for the oleander will there be no yellow leaves. Since it is a Mediterranean plant, it is also used to the sun. The direct midday sun is also tolerated without any problems if further care such as watering is right. A sunny spot sheltered from the wind on a south- or east-facing balcony or on a sun-drenched terrace is ideal. Since it is recommended to cultivate the oleander in a bucket due to its lack of winter hardiness, this also has many advantages for the summer location. Depending on the weather, it can be pushed into the sun or protected from too much rain.
Save oleanders
If the oleander looks more gray than green after hibernation and if it has lost a lot of leaves, then it can still be saved. The same applies if it has received too many nutrients or has been very wet for a long time. In such a case, it should be removed from the tub and cut.
This is done as follows:
- Cut back the plant to just above the cane
- remove from the bucket
- remove old and damp soil from the roots
- allow them to dry slightly
- Remove old soil from the pot and clean it well
- alternatively use a new vessel
- Half fill with fresh soil
- insert plant
- Add the rest of the soil, press down and water lightly
- spend in a bright, warm, sunny spot
Due to the radical pruning, it can take a year or two before the oleander blooms again, since the new shoots that will quickly form from the stock have to be a little older to form flowers. If it was the water that caused damage to the oleander, only water moderately for the first few weeks. The surface of the soil should not be soaked, but the water may remain in the plate. If too many nutrients were given beforehand, then you should not fertilize in the first time after repotting. The nutrients in the fresh soil are then completely sufficient.