If the oleander gets yellow leaves that then fall off, you should act quickly and solve the problem. Especially in summer, leaf loss is abnormal and can indicate certain diseases, care errors and pests. We explain how you can save the plant.
Oleander has yellow leaves that fall off: these are the most common causes
The oleander does best in regions with warm weather and can thrive in temperatures down to 2°C. It has difficulty withstanding permanent frost and sub-zero temperatures, which is why it is brought into its winter quarters from the end of October. In summer it prefers a location in full sun and well-drained soil. It has a medium water requirement and can easily withstand drought over long periods.
Its location requirements, temperatures and care are the reason why it is often cared for incorrectly. Since he doesn't find the optimal conditions in this country, the hobby gardener should help. That's why certain errors often occur.
The oleander has yellow, dry leaves in summer: salts in the soil
When watering it is very important that the oleander is watered extensively, very slowly and only from below. On the other hand, if you water your plant often but not enough, you will only moisten the upper layer of soil. In warm weather, the water will evaporate very quickly - but the salts it contains will remain and can accumulate in the substrate over time. The plant can then no longer absorb the irrigation water properly and dries up.
Oleander needs water when its leaves turn gray and lose their shine. Depending on the location and weather, it needs to be watered thoroughly every 3 days. You should always do a finger test first - if the top layer of soil is dry, then you can water the tree.
What you can do: If you notice white salt crystals in the substrate, the leaves of the oleander become dry and yellow, then incorrect watering / too little water is the cause.
Oleander loses leaves in summer: Too much water
If the summer is rainy, the oleander needs rain protection. The exotic prefers loamy soil, so rainwater drains more slowly and waterlogging can occur with frequent rainstorms. The result is wilted roots that can no longer absorb nutrients. In addition, the nutrients are gradually washed away, especially in potted plants. If it rains more often, nutrient deficiencies can arise after just two weeks. At the same time, wet soil and fertilizer promote fungal infestation. So you should proceed as follows:
1. First place the oleander in a rain-protected place in the garden and let the soil dry.
2. Check the soil for waterlogging. Check whether the drainage holes are blocked.
3. If the soil dries out, you can fertilize the plant and water it again.
Only the old leaves turn yellow: lack of nitrogen
If the oleander continues to produce new leaves and they are green but the others are yellowing, then it is probably due to a lack of nitrogen. But you should very muchBe careful when fertilizing– Oleander is supplied with slow-release fertilizer NPK 10-10-10 twice a year. The first fertilizer is applied in autumn, the second - at the end of May to the beginning of June.
Oleander leaves turn yellow: aphids as a possible cause
Oleander can also be attacked by aphids. This can happen both at home and outdoors. The lice are small, green and can be noticed on the lower side of the leaf upon closer inspection. The leaves yellow, dry up and curl. We already told you in our article“Yellow lice on oleander”Various natural remedies are listed that help in the fight against pests.
Yellow leaves and brown spots are a sign of oleander canker
For now: From time to time leaf fungi can attack the oleander. These are caused by yellowing leaves, which then turn brown but do not fall off. These can usually be controlled with commercially available fungicides and also with a milk solution.
However, oleanders are much more often attacked by a bacterium. In the early stages of the disease, the leaves develop many small black spots. The area around the spots yellows. Then the shoots turn dark brown. The oleander canker can also attack neighboring plants if you don't do something about it in time. At the beginning you can try to save the plant by radically pruning it back. Sick specimens are separated from the healthy ones. If pruning doesn't help, the plant can no longer be saved.
Why does my oleander get yellow leaves: checklist
If the oleander gets yellow leaves, it is worth checking the plant step by step for the following signs:
- Check the soil for waterlogging. Possible cause: Too much water. Solution – repot the oleander and place it protected from the rain. Wait until the substrate dries and only then water.
- Salt crystals in the substrate – repot the oleander and adjust the watering.
- If the substrate is moderately moist and there is no waterlogging - fertilize the oleander. To do this, use NPK fertilizer 10:10:10.
- Check the underside of the leaves for aphids.
- If there are black spots on the leaves: cut off the diseased parts of the plant immediately.
