Grapes do not grow on trees. They are the fruit of a perennial, woody vine belonging to the genus Vitis. The majority of commercially grown grapes, including those used for wine, are cultivars of the species Vitis vinifera. This climbing shrub requires external support to grow vertically and reach sunlight.
The Botanical Classification of Grapes
The botanical definition of a vine, or liana, distinguishes it clearly from a tree. A true tree has a single, self-supporting woody trunk that allows it to stand upright independently. The grapevine is a liana, a woody vine that lacks the structural strength to maintain an upright posture on its own.
In its native habitat, the wild grapevine (Vitis vinifera sylvestris) wraps and twists its way up nearby trees to compete for light. This demonstrates the plant’s inherent need for a host structure to achieve significant height. The primary stem becomes woody and permanent, and is referred to as the trunk in viticulture, but it is not self-supporting.
As a vine, the plant invests energy into rapid, flexible growth rather than developing the dense, rigid wood required for a massive trunk. The ability to climb is a survival strategy, ensuring the leaves and fruit are exposed to maximum solar radiation. An untrained plant can reach lengths of 17 meters or more, but only by relying on external support.
Understanding the Grapevine’s Structure
The grapevine’s structure is built around its climbing nature. Annual growth structures emerging from the permanent wood are called shoots. These shoots become canes once they mature and drop their leaves in the dormant season. Canes are one-year-old wood and are the main focus of pruning for managing the next season’s crop.
The tendril is the most specialized part of the vine confirming its classification. Tendrils are slender, thread-like appendages that emerge from the shoots opposite the leaves. They function by sensing and wrapping around nearby objects, providing the necessary anchor for the vine to climb and secure itself.
The permanent, older wood of the vine is composed of the trunk and the cordons. Cordons are extensions of the main trunk that growers intentionally train to grow horizontally along a wire or support structure. These cordons are wood that is two or more years old, forming the permanent arms from which the fruit-bearing canes or spurs emerge.
Why the Confusion Exists
The visual appearance of a commercial vineyard often leads to the misconception that grapes grow on small, tree-like plants. This is because viticulture involves significant human intervention to manage the vine’s natural, sprawling growth. Growers use a support system called a trellis, consisting of posts and wires, to train the vine into a neat, uniform structure.
Heavy pruning techniques, such as spur pruning or cane pruning, are used annually to control the vine’s size and shape. This meticulous management restricts the vine to a relatively short, thick trunk and a few permanent arms, or cordons, which are tied to the trellis wires. The resulting plant looks compact and self-contained, occasionally leading people to refer to them as “bush vines.”
Despite the rigid, structured appearance created by the trellis and pruning, the plant’s underlying biology remains that of a vine. If a cultivated grapevine were left unpruned and without a trellis, its shoots would immediately begin to sprawl along the ground or climb the nearest available support, just as its wild ancestors did. The vine’s reliance on external support is the definitive factor that keeps it categorized as a vine, not a tree.