Olive trees are not only pretty to look at and give balconies and terraces a wonderful Mediterranean touch, with a little luck and good care you can even harvest olives yourself. For this, however, you should have several trees, since most varieties are cross-pollinated.
Cross-pollination by genetically different second tree
The flowers of the olive tree are hermaphroditic, i. H. the flowers are bisexual, but pollination works best through a second or more olive trees. The reason for this lies in the necessary genetic diversity, because trees with different genes fertilize better than trees with the same DNA. Although self-pollination is possible under certain circumstances (e.g. with the help of a brush), it does not bring the desired yield by a long shot. Incidentally, this also applies to olive trees with the same DNA, such as those grown by propagation with cuttings - these trees only fertilize each other moderately or not at all.
pollination in olive trees
Olive trees are rarely pollinated by insects, but rather by wind pollination. The wind transfers the male pollen to the female inflorescence of the other tree. However, since olive trees in our latitudes should be kept better on the balcony or terrace for climatic reasons, wind pollination is difficult to enforce. However, you can help by hand: With the help of a brush you can transfer the pollen from one tree to the other. You can also shake the trees a little to mimic wind pollination. Olive trees usually bloom between April and June, or later when the temperatures are cooler.
Self-pollinating varieties
A few varieties are capable of self-pollination. But even with these, self-pollination only brings a very small yield, cross-pollination remains more successful and also more profitable. However, if you do not have the space for several trees, but still want to harvest your own olives, you can switch to these varieties:
- Leccino
- Francoio
- Cailletier
- Aglandou
For a higher harvest, however, at least a second olive tree, which is in the immediate vicinity of the first, would be advisable.
tips and tricks
Depending on the variety, olives have white to yellow-green flowers, which only appear when they are overwintered. In order to stimulate an olive tree to bloom, it should overwinter in a bright location at around 8 to 10 °C. It must not be fertilized during this rest period and only be watered a little.