The species Vitis labrusca Linné was established and described in 1763. Among American grapevine species, it represents the greatest interest, as its berries were initially more suitable for consumption and winemaking compared to other wild species of the New World. The species possesses sharply defined morphological characters that are stably transmitted through seed reproduction.
Historical Overview and Geographical Range
Vitis labrusca was the first American vine introduced into Europe. The earliest viticulturists in the United States, faced with persistent failures in their attempts to acclimatize European grapevines (Vitis vinifera), turned to the study of native species. They selected wild forms of labrusca with the largest berries from northern forests and propagated them by seed. Selection, sowing, and subsequent hybridization throughout the 18th and 19th centuries led to the creation of a large number of cultivars (such as Concord, Ives Seedling, Isabelle, and Hartford Prolific). These varieties formed the basis of commercial viticulture in the northern, northeastern, and central states of the USA.
Cultivars derived from V. labrusca were introduced into Europe at the beginning of the 19th century. They were imported for collections due to the specific strawberry-like, or "foxy" (French: goût framboisé, foxé) flavor of the berries. The Isabelle variety spread through France, Italy, and eastern vineyards, where the Turks cultivated it under the name Champania. Historically, it was these initial shipments of vines from America that brought powdery mildew (oidium) and later phylloxera into Europe.
At the onset of the phylloxera crisis (around 1872), when the resistance of American vine roots to pest damage was discovered, labrusca varieties (particularly Concord) began to be planted extensively in Europe. However, their cultivation on an industrial scale was soon completely abandoned. This was due to inherent and irremediable defects of the species itself. Firstly, the foxy flavor of the berries was alien to European palates, and this strong character was transmitted to the wine, persisting even after fermentation. Secondly, Labrusca proved unsuitable as a rootstock. Its resistance to phylloxera is minimal, only slightly exceeding that of European grapevines; the insect is capable of living on and destroying its roots.
The geographical range of the species is limited to the eastern and northeastern parts of the United States. The vine grows in the forests of New England and abundantly colonizes the Atlantic coast in the states of New Jersey, Delaware, Maryland, New York, and Virginia. To the south (in North Carolina and Tennessee) and to the west (in Ohio), the population of wild vines declines. According to studies by T. V. Munson, the westernmost point of the species' distribution is Grundy County in the state of Tennessee.
Ecology and Resistance Features
In its natural habitat, Vitis labrusca is rarely found on high ground or hills. It is confined to plains, lowlands, and riverbanks, preferring cool, damp locations. The species can develop normally only on very specific soils — deep, moist sands or red silico-siliceous lands resulting from the decomposition of granitic rocks.
On such suitable soils, the vine grows with great vigor. Its root system is powerful, featuring thick, fleshy roots capable of penetrating compact ground. In its native sandy soils, phylloxera forms nodules (nodosities) on labrusca roots, but the vine does not perish because pest reproduction is suppressed in sand. Under the harsh conditions of Europe — for example, in the yellow marly soils of Sandusky — Labrusca completely loses its resistance and succumbs to phylloxera within 10–20 years, exhibiting the same signs of decline as European vines. The viability of the species in France was maintained only in the light, fertile, and moist alluvial soils of alpine diluvium.
Cultivars of the labrusca species withstand the severe winter temperatures of the northern United States, from −20 °C to −30 °C, as well as summer heat up to +40 °C. The vine is characterized by very early wood maturity and early fruit ripening.
Among the primary cultural disadvantages of the species is its total lack of lime tolerance. On soils containing as little as 10% chalk, Labrusca vines suffer from lime-induced chlorosis and soon perish. The species is resistant to oidium and downy mildew (mildew) but is severely affected by black rot (Black-Rot). However, labrusca cuttings root easily, and its shoots share a high anatomical similarity with V. vinifera, ensuring excellent graft affinity and abundant callus formation during grafting.
Anatomical and Morphological Description
Vine: Highly vigorous, with a trailing or climbing habit. In forests, the vine climbs trees and shrubs, developing a massive trunk. The trunk diameter of wild specimens in New Jersey reaches 20–25 cm. The wood is soft, brittle at maturity, light green on the inside when cut, and exhibits a brick-red tint beneath the exfoliating strips of bark. The bark is brownish, detaching in long, regularly interlacing wide strips.
Shoots: Very long, thick, cylindrical, straight, with weakly defined nodes. Internodes are of medium length, with numerous fine but distinct striations. In the herbaceous state, the shoots are dirty green, covered with a dense whitish or golden-yellow felt-like tomentum, which thickens at the apex. Upon lignification, the canes become chocolate-brown or dark purple, matte, with weak segregation into color zones; the tomentum persists on them in sparse flakes. The nodes bear numerous short, stiff multicellular hairs; in some wild forms from Maryland, these hairs cover the internodes as well, making the shoot rough to the touch after they shed in summer. The pith is wide, occupying more than half the shoot diameter, loose, and pinkish-brown. The diaphragms at the nodes are nearly flat and thick (2–3 mm). Tendrils are powerful, long, bi- or trifurcated, and covered with down. A diagnostic feature of the species is the continuous arrangement of tendrils on the shoot (or sub-continuous in some wild types) (Fig. 641).
Buds: Large, short, conical, surrounded by sparse rusty-brown (ferruginous) hairs.
Leaves: Large, sub-orbicular, the length being nearly equal to the width (dimensions vary from 17×15 cm to 25×24 cm), practically symmetrical. The blade is entire or with three weakly defined lobes separated by shallow, acute sinuses; the lower lateral lobes are indistinct and marked only by a more developed marginal tooth. The leaf blade is thick, brittle, with a strongly bullate (bullées) and finely rugose upper surface. The petiolar sinus (sinus basilaire) is deep, V-shaped, with rounded margins that often overlap at the insertion of the petiole. The upper surface of the leaf is deep green, matte, with sparse arachnoid hairs along the sunken main veins. The lower surface of the leaf is completely covered with a dense, felted, interlaced tomentum (tomentum feutré) that conceals the spongy tissue (parenchyme). The tomentum is whitish or golden-yellow, turning rust-colored in the southern states. The main veins are strongly prominent on the lower surface and are yellowish in color. The petiole is short, thick, channeled, covered with felted and stiff hairs, and sets at a right angle to the leaf blade.
Young Leaves: Flat, tinged with an intense dark carmine color from the moment they emerge from the bud. This pigment persists for a long time on the lower surface beneath the dense down. The coloration of the upper surface is golden-yellow, and the margins of the teeth are carmine.
Flowers: Small, gathered in small inflorescences covered with light down. At the apex of the corolla (calyptra), the buds have a dirty red coloration. Staminal filaments are long and thick; the sub-pistillic disc is weakly developed. The ovary is small, with a long style continuous with the stigma.
Berries and Bunches: The bunch is small or medium, cylindro-conical, loose, with berries loosely arranged; branching (wings) is rare. The peduncle is short, of medium thickness, herbaceous, and soft at the base. Pedicels are short, with a large, weakly verrucose torus. Berries are large, globose, covered with a glaucous waxy bloom (pruina). In wild forms, the skin color ranges from greenish-white to black, but most frequently the berries are red-purple. The skin is very thick, tough, and leathery (coriace). The pulp is firm, mucilaginous, not very juicy, with a pronounced foxy (strawberry-like) flavor. Under natural conditions, the ripening of berries within the bunch is uneven.
Seeds: There are 2–3 seeds per berry. The seeds are large, short, round-trigonal or flattened (7–8 mm long, 4–5 mm wide), dark chocolate-brown, smooth, and shiny. Inside the depressions and in the chalazal depression, the color of the seed is light yellow. The beak (bec) is short, thin, and sharply separated from the body of the seed. A true chalaza and seed groove (raphe) are absent; in their place on the dorsal side of the seed is a deep, circular depression from which a distinct groove originates, running around the bilobed base (Fig. 639–640).
