A grapevine is a woody, perennial climbing plant belonging primarily to the genus Vitis, cultivated globally for its fruit. As a deciduous vine, it sheds its leaves seasonally but returns to grow and produce fruit year after year. The grapevine’s unique structure and growth habit allow it to climb and spread, making its distinct visual components key to identification. A closer look at its various parts reveals a complex and fascinating organism.
Overall Growth Pattern and Vine Structure
The natural habit of a grapevine is that of a vigorous climbing vine, seeking support structures to ascend. In the wild, a vine can sprawl up to 50 feet, using other plants and trees for support. The plant is perennial, with its root system and permanent woody structure surviving the dormant winter season.
Cultivated grapevines are highly structured and trained along support systems like trellises or arbors. This training helps manage the canopy for optimal fruit production and light exposure. The main permanent stem is called the trunk, and it often extends horizontally into semi-permanent arms known as cordons. Cordons are tied along a wire to create a defined structure from which the annual growth emerges.
The Distinctive Appearance of Leaves and Tendrils
Grapevine leaves are a primary identifying feature, typically large, broad, and lobed, often resembling a maple leaf. They are usually three- or five-lobed and have coarsely serrated edges. The leaf blade can range from three to over eight inches wide, with the width similar to the length.
The internal structure is marked by a palmate venation pattern, where three or more main veins radiate outwards from the point where the petiole (leaf stem) attaches. Crucially, the vine uses specialized, string-like organs called tendrils for attachment and climbing.
Tendrils are long, winding protrusions that coil tightly around any object they encounter, anchoring the vine to its support. These tendrils grow opposite a leaf at the nodes along the shoot. They are the vine’s primary method of grasping a trellis wire or neighboring branch, allowing the plant to climb upward.
Identifying the Woody Canes and Bark
The grapevine’s woody structure is divided into permanent wood and annual growth. The oldest wood, comprising the main trunk and cordons, develops rough, shaggy, or peeling bark as it ages due to the formation of a cork layer. This older bark often appears dark brown and cracks as the plant expands.
The new, one-year-old growth is referred to as canes. Once mature and dormant, canes are visually distinct, having smoother, light tan or cinnamon-colored bark, contrasting with the darker, rougher permanent wood. Canes are partitioned by nodes, which are slightly thickened sections where leaves, tendrils, and buds emerge, separated by smooth internodes.
The Appearance of Grape Clusters
Fruit production begins with small, inconspicuous flowers that form in clusters called inflorescences. These tiny flowers lack showy petals, as they are fused into a protective cap called the calyptra, which detaches and falls off as the flower opens. Grapevines are typically self-pollinating, meaning the flowers possess both male and female parts and do not require insects for fertilization.
Following successful fertilization, the inflorescence develops into a cluster or bunch of grapes. The cluster structure is built around a central stem called the rachis, with individual round to oval berries attached to short stems, or pedicels. The overall shape of the bunch is often conical or cylindrical, varying significantly between grape varieties.
As the fruit ripens, a process called veraison occurs. During veraison, the berries change color from green to shades of red, purple, or yellow, while simultaneously accumulating sugars.