From the “Polyconic Vase” to the Free “Zaragoza” Vase: Transforming Traditional Olive Groves for Modern Olive Cultivation

In the territory of Rieti, the most widespread training system in traditional olive groves is the Polyconic vase. This structure is based on a trunk from which four or five main axes develop, distributing sap and production along the lateral branches.

For many years this system has represented, and still represents, a significant evolution compared with older headless training forms. However, when viewed through the perspective of modern olive cultivation, several limitations become evident. The main issue is not productivity itself, but rather plant balance and management costs.

Over time these trees tend to grow considerably in height, easily reaching six to seven meters while developing a large woody mass that is often disproportionate to the leaf surface. To sustain such a structure, the tree must continuously produce new active foliage and reacts by emitting numerous vigorous shoots, particularly along the inclinations of the main branches.

Two or three years after pruning, the result becomes clear. The inner part of the canopy fills with vigorous and disordered vegetation, to the detriment of the lateral fruiting branches, which gradually weaken. At the same time there is an increase in vigorous water sprouts that do not contribute to production but instead represent the tree’s response to the imbalance between woody mass and leaf surface.

This situation creates a true vicious cycle. The tree is pruned to contain its growth, it reacts with strong vegetative vigor, and after only a few years significant internal cleaning operations become necessary again. The outcome is many working days, heights that are difficult to manage, and large quantities of removed wood that make the system incompatible with current agricultural efficiency requirements.

In reality, the water sprout is not the problem to eliminate, but rather the signal of an unbalanced tree.

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For this reason, the approach proposed by agronomist Vito Vitelli involves the gradual transformation of these orchards through a more rational management of vegetative structure.

The strategy is based on two operational principles:

• Increasing planting density along the row by introducing new trees between the existing ones
• Resizing old trees through reform pruning, which involves reducing the height of the canopy by cutting the trunk drastically at about 110 to 120 centimeters and then restructuring the plant. Within three or four years the tree returns to production.

Through this process a new vegetative architecture begins to develop. With two or three spur pruning operations at approximately 15 to 20 centimeters, together with topping and edging according to the principles of the Zaragoza system, multi branching is stimulated. This gradually leads to the formation of a compact and free productive bush characterized by a series of vertically oriented shoots.

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The tree consequently assumes a cylindrical or truncated cone shape. It does not grow excessively in height, becomes easily manageable from the ground, and when planting distances allow it, it is also suitable for harvesting with a shaker equipped with an umbrella.

The structure of the tree changes completely. It becomes lower, more balanced, and easier to manage. Vegetation naturally bends outward, creating a productive wall rich in fruiting branches. Under these conditions the tree no longer reacts by producing vigorous water sprouts, but instead forms strong and productive fruiting branches that quickly enter production.

The transition is therefore from tall and difficult to manage trees to compact, pedestrian, and well illuminated plants where pruning becomes a simple and intuitive operation. Interventions are limited to a few targeted renewal cuts, opening the cone of light, and managing the branching structure within what can metaphorically be described as the “palm of the hand.”

The result is a far more efficient system: less woody mass to sustain, greater light interception, and improved distribution of resources toward fruiting branches and the production of olives and consequently olive oil.

Under these conditions pruning can be performed entirely from the ground in significantly reduced time, often requiring only four to five working days per hectare, equivalent to roughly four to five minutes per tree.

The transformation from the traditional Polyconic vase system to a free bush style Zaragoza vase therefore represents a concrete response to the needs of contemporary olive cultivation: lower, balanced, productive trees that are truly sustainable from both an economic and management perspective.

Official Editorial Note
Original content by agronomist Vito Vitelli, developed and optimized with the support of artificial intelligence tools for educational, informational, and technical dissemination purposes.

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