Ferocious Focus,  Grape Cultivation

Ferocious Focus: Trellis Systems

“Trellis systems” is a large topic to tackle in a single post. The plan is to provide a shorter explanation here to set up for a longer post next week on a specific trellis system that I have often seen used in Nagano, Japan. And, no, it is not the pergola-like budodana system. Although that is an interesting system in itself and should get a post at some point.

What is a Trellis System?

So, as mentioned, “trellis systems” is a large topic. To start, let’s be specific about what a trellis system is and how it is different from training systems and pruning. Jancis Robinson’s The Oxford Companion to Wine provides a nice explanation and below is a summary of that:

  • Trellis system: a man-made physical structure, consisting of posts, generally made of wood and wires
  • Training system: training is the action of pruning in winter and summer so that the vine’s various parts (e.g., trunk, arms, cordons, buds) are appropriately located on a trellis system; training systems often take the name of the trellis it does the training for
  • Pruning: divided into winter pruning, which is cutting off unwanted vegetative parts of the vine during the winter to prepare it for the next growing season, and summer pruning, which is basically trimming

Types of Trellis Systems

There are several types of trellis systems. The simplest type is a stake  driven into the ground to which the vine is tied. More complicated types consist of multiple wires and training vines vertically upwards and downwards as well as horizontally. Some examples are the Geneva Double Curtain or the U-shaped Lyre systems. An increasingly common type is the vertical shoot positioning system (VSP). In this system, movable wires allow shoots to be trained into a narrow vertical canopy.

Vertical shoot position (VSP) trellis system. Photo by Andy Allen, University of Missouri.

Why use a Trellis System?

Grape growers choose trellis systems to manage the vine canopy and the vines’ growing conditions. For example, VSP allows the grape grower to separate where grapes grow and where leaves grow. This allows greater air circulation around the grapes and decreases fungal disease. It also maximizes the amount of sunlight the grapes and leaves receive maximizing photosynthesis and ripening. In hot, sunny climates, grape growers may choose to not trellis vines in order to keep shade and prevent the grapes from burning.

With this background on trellis systems, check in next time for an in-depth look at a trellis system often used in Nagano to manage the vines in that region’s fertile soil and wet environment.

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