In Spain or Italy, oleander grows almost everywhere, the main thing is that it is nice and warm, sunny and also moist. In contrast to many other Mediterranean plants, oleander needs both a lot of water and a lot of nutrients - the shrub is a real “glutton”. The factors mentioned must all come together so that the oleander feels comfortable and produces the lush flowering it is hoping for.
Various causes of missing flowers
Now it's not that rare that the oleander grows wonderfully, but not a single flower wants to show itself. Or the bush forms countless buds, but instead of breaking them, they fall off. The possible reasons for this are very complex.
Wrong location
Probably the most common reason for oleanders not blooming is the location. If the plant does not feel comfortable there, it will not form any buds at all or will drop them again. Place the shrub in full sun and in a location that is as warm and protected as possible, i.e. H. it should not be directly in the draft. The cold at night can also be to blame for the lack of flowering, especially when temperatures drop below 18 °C at night. In this case, the leaves of the oleander often 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 if the summer is cold and rainy: the oleander does not like such weather and it reacts accordingly. Since you can't do anything about a summer period of cold and rain, all you can do in this case is hope for next summer.
Incorrect pruning
Incorrect pruning can also rob the oleander of its flowers, for example by cutting off spent inflorescences. With other plants, such measures ensure further flowering, but not with oleander: it forms the next flower directly at the tip of the old inflorescence. For this reason, you should only pluck the dried petals, but not cut off the entire inflorescence.
Nutrient and/or water deficiency
As already mentioned, the oleander is a very hungry fellow, even though it is a Mediterranean plant. If you don't provide it with enough water and/or nutrients, it will remain quite lazy to bloom. Adequate watering and quick-acting instant fertilizers for flowering plants (€10.00 on Amazon) can help. Oleander should be fertilized at least once a week. If possible, use stale tap water instead of rain.
Tip
In general, oleanders with double flowers are much more demanding than the varieties with simple, unfilled ones and are therefore much more difficult to get to bloom. Oleanders with double flowers not only need sun, warmth, water and nutrients, but also protection from rain and similar weather hazards. It is best to plant these varieties directly in front of a warm house wall or, ideally, under a roof overhang, which, however, should not cast any shadow on the oleander.
