The grape plant, belonging to the genus Vitis, is a perennial woody vine cultivated globally for its fruit. This plant is a deciduous species, shedding its foliage in the winter months and renewing its growth each spring. Grapes have been cultivated for thousands of years, primarily for fresh consumption, drying into raisins, or fermentation into wine.
The Overall Growth Habit
The grape plant’s defining characteristic is its climbing growth habit, which allows it to sprawl extensively if left unsupported. In nature, the vine uses its flexible structure to ascend trees and other vegetation, reaching heights of 40 to 60 feet. The collective mass of shoots, leaves, and fruit is known as the canopy, which is the primary site for photosynthesis and energy production.
In cultivation, the vine’s sprawling nature requires training onto support systems like trellises or arbors to manage the canopy and optimize fruit exposure to sunlight. The vine’s growth is partitioned into nodes, which are slightly thickened sections where leaves and other structures emerge, and internodes, the sections of stem between the nodes. This structural organization facilitates the rapid expansion of the vine during the growing season.
Identifying Features: Leaves and Tendrils
A grape leaf is easily recognizable by its shape, which is typically orbicular or heart-shaped with distinct palmate lobes. Most varieties feature three to seven lobes, giving the leaf a hand-like appearance, and the edges are coarsely toothed or serrated. The size of the leaf blade can vary significantly, often measuring between 3.5 to 11 inches across, depending on the variety and growing conditions.
The leaf texture can range from smooth on the upper surface to having a duller color and exhibiting woolly or bristly hairs on the underside. Emerging opposite many of the leaves are the vine’s specialized grasping organs called tendrils. These slender, thread-like structures are modified shoots that coil tightly around any nearby support, acting as a grappling hook to secure the vine’s weight as it climbs. Tendrils are sensitive to touch, which triggers the coiling mechanism necessary for attachment.
Woody Structure: Trunks and Canes
The base of the vine is the trunk, a thick, woody structure that supports all above-ground growth. As a grape plant matures, the bark on the trunk becomes noticeably gnarled and begins to peel or shred in strips, revealing the older, darker wood underneath. The height of the trunk is determined by pruning and the training system used in the vineyard.
The annual growth is categorized into shoots and canes. Shoots are the succulent, green growths produced during the current season, which bear the leaves, tendrils, and fruit. Once these shoots mature, drop their leaves, and become dormant in the fall, they lignify into one-year-old wood, known as canes. Canes are typically light tan or cinnamon-colored, distinguishing them from the darker bark of the older wood.
Flowers and Fruit Clusters
The reproductive structures of the grape plant begin with small, often inconspicuous flowers that are grouped together into dense formations called inflorescences. These flowers are greenish in color, typically measuring only a few millimeters in length, and lack the showy petals found on many other plants. Instead, the petals are fused into a cap-like structure called the calyptra, which detaches and falls off as the flower opens.
The fertilized flowers eventually swell to become the grapes, which are botanically classified as berries. These berries are held together in the characteristic pendulous bunch, or cluster, structure by a main stem called the rachis. Grape clusters vary widely in size and shape, and the individual berries can ripen to a diverse palette of colors, including green, gold, red, purple, and nearly black.