Grapes are the fruit of the woody, perennial vine belonging to the genus Vitis. This climbing organism has been cultivated by humans for thousands of years. Because of its inherent growth habit, the vine requires a structure to support its weight, which increases with age and fruit production. Understanding what grapes grow on involves looking at both the plant’s biological structures and the man-made support systems developed through centuries of viticulture.
The Nature of the Grape Vine
The grapevine is classified as a liana, which is a type of woody vine that climbs other plants or structures to reach sunlight. The permanent, thick base of the plant is called the trunk, which supports the one-year-old growths known as canes and the current season’s green growths, or shoots. It is the shoots that bear the leaves, and most importantly, the clusters of grapes.
To facilitate climbing, the grapevine produces specialized, slender organs called tendrils. These tendrils appear opposite a leaf on the shoot and coil tightly around any nearby object, creating a strong anchor. As the season progresses, these initially soft tendrils become woody and hardened, providing a permanent grip. This mechanism allows the vine to distribute its weight and maximize the exposure of its leaves to the sun.
Essential Support Systems
Growers must provide artificial support structures to control the plant’s shape and maximize yield quality. The most common commercial method is the trellis system, which consists of wooden or metal posts connected by high-tensile wire strung between them. Trellises are designed to hold the permanent wood (cordons) and the fruiting canes in a fixed plane, often three to six feet above the ground.
The specific design of the trellis system is often tailored to the grape variety’s natural growth habit. For example, many European wine grapes (Vitis vinifera) are trained on Vertical Shoot Positioned (VSP) systems, where shoots are guided upward and contained by parallel catch wires. For home gardeners, arbors and pergolas are frequently used, allowing the vine to grow horizontally overhead and create shade. Proper support ensures adequate air circulation around the grape clusters, preventing fungal diseases, and ensures the fruit receives sufficient sunlight for ripening.
Longevity and Maintenance
Grapevines are resilient perennial plants that can remain productive for many decades, sometimes reaching over a century in age. This long lifespan is dependent on a precise, annual practice known as pruning. Pruning is performed during the dormant winter season, when the vine has dropped its leaves, making the structure visible.
The purpose of this yearly maintenance is to balance vegetative growth with fruit production for the upcoming season. Growers must remove most of the previous year’s growth because fruit is only produced on shoots that grow from one-year-old wood. Careful pruning limits the number of buds, concentrating the plant’s energy into producing fewer, higher-quality grape clusters. This annual removal of wood also ensures the vine remains manageable on its fixed support system and prevents the fruiting wood from migrating too far from the main trunk.