The olive flower or the “rapa”. Some interesting facts!

14-05-2021

The olive flower or the “rapa”. Some interesting facts! If there is one crucial moment for the Olive tree that determines the following year's harvest, it is the flowering phase. This stage, when the olive tree is covered with flowers, is worth admiring, but it is also the most critical part of the process.

Moreover, if you are allergic to olive tree pollen (a very common allergy in Jaén), you will understand perfectly why pollen is in the air after reading this article. We describe all the peculiarities of the olive flower and its blooming stage!

Blossoming/Flowering

The olive blossom is called rapa, although depending on the geographical area, it is also known as trama, cadillo or esquimo.

The rapas grow in clusters of between 10 and 40 flowers, depending on the variety. Each of these flowers has four white petals and an orangey-yellow centre, which gives that beautiful colour to the sea of olive trees in bloom.

Flowering in each rapa lasts about a week, so this phase is short-lived. In total, this stage lasts three weeks from the time the first olive blossom opens until the last blossom is fertilised (or falls).

When does it occur?

When the average daily temperature exceeds 18ºC, which happens in mid-May. This is when the flowering stage begins. Depending on the climatic conditions and the growing area, an olive tree can begin earlier or later in this period.

Apart from the climatic conditions, it also depends on the variety of the olive tree. Thus, some early flowering varieties are ocal or farga; medium flowering, picuda and picual; and late flowering, blanqueta and arbosana.

Flower pollination

The flowers of olive trees have a distinctive characteristic: they have two types of flowers.

- Hermaphrodite flower. They have both reproductive apparatus: pistil and stamen, where pollen is created. Hermaphrodite rapas have the possibility of fertilising and being fertilised. They are the ones that produce fruit.
- Male flower. They only have stamens, so they produce pollen but cannot produce fruit.

Pollen from one olive tree can travel hundreds of kilometres to pollinate flowers from other olive trees, as it cannot fertilise the rapas from the same olive tree or from nearby olive trees if it recognises them as belonging to the same family. For this reason, there are more than 250 varieties of olives and olive trees. It is very common for pollen produced in Andalusia to fertilise olive trees in Morocco and vice versa.

Only 2% of the total number of flowers of each olive tree are pollinated. From this percentage of fertilised flowers, the olive tree itself performs a 'sieve' function and will only keep the strongest and healthiest fruits that can ensure the nourishment and proper growth of its seeds: the olives, which can later be converted into olive oil.

Why is this the most critical stage?

The flowering of the olive tree is the most critical stage of the whole cycle as it is the one that determines the productivity of the following harvest. If flowering is poor, the next harvest will be poor.

The weather conditions during flowering can affect this phase of the olive tree. In many cases, temperatures often rise when the olive trees are in bloom, or there are heavy frosts and rains. This can cause a weakening of the flowers themselves, which will not germinate and produce fruit.

Flowering is one of the most vulnerable stages of the olive tree and decisive for the harvest of the following year. It ends when the rapas detach their petals, a sign that they have already been fertilised, and the beginning of the new fruit: the olive.

 

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