The common belief that grapes grow on trees is a misunderstanding, often because the plants appear to be self-supporting. The grapevine is fundamentally not a tree, which is defined by having a structurally independent, woody trunk capable of holding up its own canopy. Resolving this confusion requires understanding the plant’s natural biology and the extensive manipulation involved in commercial cultivation. The structure seen in vineyards is a managed system designed to maximize yield and fruit quality, not the plant’s inherent form.
Defining the Grapevine: A True Liana
The grapevine belongs to the genus Vitis and is botanically classified as a liana, a type of long-stemmed, woody vine rooted in the soil. Unlike a tree, which possesses a rigid, self-supporting trunk, the grapevine’s stem is naturally flexible and cannot maintain an upright position on its own. If left to grow without any external support, the plant would naturally trail along the ground.
The plant compensates for its lack of structural support by developing specialized grasping organs called tendrils. These slender, coiled structures grow opposite a leaf and wrap tightly around any object they encounter, such as tree limbs or rocks. Tendrils are modified shoots that provide the anchoring strength for the vine to climb, allowing the leaves to reach sunlight for photosynthesis. As the growing season progresses, these tendrils thicken and become woody, permanently securing the vine to its support structure.
Training and Trellising: Why They Look Like Trees
The upright, tree-like appearance of vineyard grapes is the direct result of human intervention through a process known as training and trellising. The main, permanent stem that rises from the ground is called the trunk, which is established by selecting and vertically training a single, strong shoot during the first few years of growth. This trunk is kept relatively short and is secured to a stake or the lowest wire of the support system to give it stability.
From the top of this permanent trunk, vineyard managers train horizontal extensions known as cordons, or arms, along a supporting wire. This trellis system, which consists of posts and wires, is entirely artificial and provides the physical structure the plant lacks. Systems like the bilateral cordon or Vertical Shoot Positioned (VSP) are designed to manipulate the vine’s growth, ensuring even distribution of fruit and foliage. This manipulation gives the illusion of a self-supporting canopy, though the weight of the vine and its fruit is borne by the external trellis.
Common Grape Varieties and Their Uses
The diverse family of grapes is split into distinct varieties used for various purposes, depending largely on their species of origin. The vast majority of the world’s wine and high-end table grapes belong to the species Vitis vinifera, originally from the Mediterranean region. These grapes, which include popular types like Merlot, Sauvignon Blanc, and most seedless green and red table grapes, are favored for their balanced flavor and texture.
North America is home to several other native species, such as Vitis labrusca, most famously the Concord grape. Concord grapes are characterized by a distinct, earthy aroma often described as “foxy” and are primarily processed into juice, jelly, and preserves. Another native species is the Muscadine, Vitis rotundifolia, which thrives in the warm, humid climate of the southeastern United States. Muscadines are recognized for their thick skin and are used fresh as a table grape, as well as for making specialized sweet wines and jams.