VITIS RIPARIA

'''Vitis riparia''' Michx, also commonly known as 'River Bank Grape' or 'Frost Grape', is a native American climbing or trailing vine, widely distributed from Quebec to Texas, and Montana to New England. It is long-lived and capable of reaching into the upper canopy of the tallest trees. Mature vines have loose, fissured bark, and may attain several inches in diameter. Leaves are alternate, often with opposite tendrils or inflorescences, coarsely toothed, 5–25 cm (2–10in) long and 5–20 cm (2–8in) broad, sometimes with sparse hairs on the underside of veins.
The inflorescence is paniculate 4–15 cm (1.5–6 in) long and loose, and the flowers are small, fragrant, dioecious, and white or greenish in color. ''V. riparia'' blooms in May or June and produces a small 6–15 mm blue-black berry (grape) with a bloom, seeded, juicy, edible, vinous-herbacous in flavor (not foxy), but usually sour. ''V. riparia'' has a wide range and may deviate considerably in detail from the above general description. White berries, perfect flowers, large clusters, large berries, and sweet fruit are among the known variations. However, some observers consider such variations as evidence of natural hybridization with other species of grapes.
Some ''V. riparia'' vines have been known to withstand −42 °C (−45 °F). The foliage is typically resistant to mildew and black rot, and the roots resistant to phylloxera. The berries however, are often sensitive to mildew and black rot if the vine is exposed to prolonged wet and humid conditions. ''V. riparia'' is sometimes used to make flavorful homemade jellies, jams, and wine. It is also used extensively in grape breeding programs to transfer cold hardy and disease resistant genes to domesticated grapes. The French-American Hybrid grapes are notable examples of these winemaking programs. ''V. riparia'' hybrids are being investigated by the University of Minnesota's horticulture program (the same program that created the Honeycrisp apple) in an effort to make a commercially viable wine grape that can survive the northern climate of the Upper Midwest.