Grapevines, belonging to the genus Vitis, are perennial plants distinguished by their woody, climbing habit. These deciduous vines are cultivated globally, forming the foundation of both the table grape industry and viticulture. Their unique growth pattern combines a permanent wooden structure with extensive annual growth, necessitating specific training systems to manage the plant’s vigor for efficient fruit production.
Primary Identification Markers: Leaves and Tendrils
The most immediate visual identifiers of the grapevine are its large leaves and its unique climbing structures, the tendrils. Grapevine leaves are characteristically broad and possess a distinctive, deeply lobed or sometimes heart-shaped form, often compared to the shape of a maple leaf. The blade of the leaf is typically large, ranging from three to eleven inches long and wide, with edges that are coarsely toothed or serrated.
The surface of the leaf can vary by species and variety, with some having a smooth texture while others exhibit a fuzzy or downy underside. Prominent veins radiate outward from the point where the leaf stem, or petiole, attaches to the blade, creating a clear structure. The vine secures itself to supports using tendrils, which are modified stems that appear as slender, winding protrusions.
These tendrils grow in a tight, spiraling manner and coil firmly around any object they touch, anchoring the vine as it climbs. Along a new shoot, a tendril typically emerges opposite a leaf. After the growing season ends, these tendrils harden and become woody, helping to stabilize the vine’s position over the winter.
The Woody Structure: Trunk and Canes
The permanent structure of the grapevine consists of the trunk and the older, semi-permanent branches that develop from it. A mature grapevine trunk is a thick, gnarled structure that provides support and acts as the main conduit for water and nutrients from the root system. The bark on older wood is easily identifiable by its textured, layered, and often shredded or peeling appearance, which results from the formation of a cork layer beneath the surface.
From the trunk extend the cordons, which are semi-permanent, horizontal extensions trained along a trellis wire. Cordons are composed of old wood, which is dark brown or gray and stores carbohydrates during dormancy. Canes are defined as the one-year-old growth, which were the green shoots of the previous season that have matured, dropped their leaves, and turned woody.
Canes range in color from light tan to dark brown and are distinguished by a smoother bark texture compared to the older, deeply fissured trunk. These canes are particularly important because they contain the buds that will produce the fruit-bearing shoots in the upcoming season. The canes and cordons work together to define the vine’s cultivated shape, supporting the annual cycle of growth and fruit production.
Appearance Across the Seasons
The visual appearance of a grapevine undergoes dramatic changes throughout the year, marking the transition from dormancy to a lush, fruiting plant. During the winter, the vine is leafless, appearing as woody, brown or gray trunks and pruned canes. The plant’s activity is minimal, but the compound buds that will produce the next season’s growth are protected within the nodes of the canes.
The beginning of spring is often heralded by “bleeding,” where sap leaks from pruning cuts as the soil warms. Soon after, bud break occurs, revealing the first tiny, fuzzy green shoots that rapidly grow into new stems, leaves, and tendrils. These new shoots develop small, greenish, and often inconspicuous flowers arranged in conical clusters.
The fertilized flowers quickly transition into small, hard, green spheres, forming the immature grape clusters. By late summer, a process called veraison begins, where the berries expand, soften, and change color, with red varieties developing their pigments and white varieties turning a more translucent yellow-green. The growing season concludes in the fall as the leaves change color to brilliant yellows, reds, and purples before they drop, allowing the vine to store energy for the coming winter and return to its dormant state.