Basically, yellow leaves on oleander are a completely normal phenomenon and nothing to worry about. Although this plant is an evergreen species, the foliage is subject to aging and is shed after two to three years and replaced by fresh green leaves. However, reasons other than the cause listed here can also lead to yellowing of the leaves.
Why does my oleander have yellow leaves?
Yellow leaves on oleander can be caused by an unfavorable location, lack of nutrients, lack of water or overwintering that is too warm. Adjusting the site conditions, fertilization and irrigation can help.
Inappropriate location
Oleander loves a warm place in the sun, which should also be protected from the wind. The Mediterranean plant cannot tolerate wind and turns yellow. Changing location is also problematic, for example when moving from winter to summer quarters. This should always be done carefully and in stages so that the plant can get used to it.
Nutrient Deficiency
If a lot of leaves turn yellow in a short time, this can indicate a nutrient deficiency. The oleander is a heavy feeder and therefore needs to be fertilized regularly - especially if it is cultivated in a bucket. If fertilization is insufficient, the yellow leaves are an indication of a deficiency, often of nitrogen and/or potassium. Fertilize oleander at least once or even twice a week during the growing season with a good flowering plant fertilizer (€14.00 on Amazon).
Water shortage
In its natural habitat, the oleander likes to grow on river banks that are flooded from time to time. The plant is used to frequently having wet feet. Oleander needs a lot of water and is one of the few species that can tolerate waterlogging. If there is a lack of water, the leaves can turn yellow and eventually be dropped.
Warm wintering
Another common cause of the yellow leaves of the oleander can be overwintering that is too warm, for example if you put the plant in the warm living room in the cold months. In winter, the evergreen oleander needs a break, so you should place it in a cool, but frost-free and bright place. The lack of winter light can also cause yellow leaves.
Tip
If other causes are not an option, check the size of the bucket. Choose the container size as large as possible, as the oleander's roots need space. The plant should also be repotted once a year.