In Spain or Italy, the oleander grows almost everywhere, the main thing is that it is nice and warm, sunny and also humid. In contrast to many other Mediterranean plants, oleander needs a lot of water as well as a lot of nutrients - the shrub is a real "glutton". The factors mentioned must all come together so that the oleander feels good and develops the hoped-for lush bloom.
Care mistakes are often the reason for the lack of flowering
Various causes of missing flowering
It's not that uncommon for the oleander to grow wonderfully, but not a single flower will appear. Or the shrub develops countless buds, which do not break open, but fall off. The possible reasons for this are very complex.
Wrong location
Probably the most common reason for the oleander not flowering is the location. If the plant does not feel comfortable with this, it will not form any buds at all or will shed them again. Place the shrub in full sun and in a location that is as warm and sheltered as possible, i. H. it should not be directly in the draft. Incidentally, the cold at night can also be to blame for the lack of flowering, especially when temperatures drop below 18 °C during the night. In this case, the leaves of the oleander often also react and turn yellow to brown due to metabolic problems.
The flowers fail in cold, rainy summers
The lack of flowering should not surprise you when the summer is cold and rainy: the oleander does not like such weather and reacts accordingly. Since there is nothing you can do about a summer cold and rainy spell, all you can do in this case is hope for the next summer.
Wrong pruning
Incorrect pruning can also rob the oleander of its flowers, for example by cutting off faded inflorescences. With other plants, such a measure ensures another bloom, but not with the oleander: This forms the following bloom directly at the top of the old inflorescence. For this reason, you should only pluck off the dried petals, but not cut off the entire inflorescence.
Nutrient and/or water deficiencies
As already mentioned, the oleander is a rather hungry fellow, despite being a Mediterranean plant. If you don't provide it with enough water and/or nutrients, it will remain quite lazy. Sufficient watering and fast-acting instant fertilizer for flowering plants can help. Oleander should be fertilized at least once a week. If possible, do not use rainwater for watering, but use stagnant tap water.
tips
In general, oleanders with double flowers are much more demanding than the varieties with single, unfilled flowers and are therefore much more difficult to get them to flower. Oleanders with double flowers not only need sun, warmth, water and nutrients, but also protection from rain and similar bad weather. It is best to plant these varieties directly in front of a warming house wall and ideally under an overhanging roof, which, however, must not cast any shadows on the oleander.