Vitis riparia

Vitis riparia (synonyms V. odoratissima, V. vulpina or V. cordifolia), commonly known as frost grape or riverbank grape, is a beautiful wild vine native to North America, introduced to France as a rootstock for its resistance to phylloxera, a formidable parasite that decimated the French vineyard in the 19th century. It is also used as an ornamental climbing plant because it produces a sour black grape of poor taste. In early summer, its cream-white flowering, in vaporous clusters, is both melliferous and pleasantly fragrant. Its grapes ripen in September, somewhat softened by the autumn frost, and are used to make jellies in North America. It is appreciated for its hardiness, its charm as a wild plant, and its beautiful autumn colours. Very hardy and not demanding in terms of soil, it thrives in the sun and prefers loamy, fertile soils.

Riverbank grape belongs to the vitaceae family. Native to eastern North America, it grows spontaneously from southern Canada to Oklahoma and Arkansas. It has naturalised in the Mediterranean region where it hybridizes with wild grape (Vitis vinifera subsp. sylvestris). Many hybrids have been created to vary u, flavours, and uses. Frost grape is a vigorous, fast-growing sarmentous shrub, capable of living for many years in the garden. This fast-growing plant can send its stems up to 18-20 metres (59-66 feet) depending on growing conditions. It spreads both by its seeds, dispersed by birds, and by producing shoots. Its final shape will depend on the pruning practiced. The vine attaches itself to its support (trellis, espalier, etc.) thanks to its tendrils and prefers sunny locations. The foliage of Vitis riparia is deciduous, appearing in spring and falling in autumn. The heart-shaped leaves, 7 to 15 cm (3 to 6in) long, have toothed edges. They sometimes have 3 slightly marked lobes. The lamina is medium green, turning orange to red tones in autumn. This species is dioecious: there are male and female plants. Only the females produce fruits. Flowering occurs in June, often as early as May in mild climates. Panicles of 5 to 15 cm (2 to 6in) long, composed of numerous tiny cream-coloured flowers with a sweet fragrance, form at the leaf axils. After pollination, grapes form in small clusters, more or less tightly packed together. These round grapes, 9 mm (<1in) in diameter, start off green and ripen in September-October, earlier in the south than in tnorthern or central regions. They are blackish-blue when ripe, with thick and powdery skin. The pulp is very acidic and contains seeds. Any other vine that flowers at the same time can pollinate it.

Resistant to mildew and phylloxera, this vine avoids repeated treatments and promotes biodiversity in the garden. It is indifferent to soil types but thrives in deep, loamy, and fertile soils. Riverbank grape climbs willingly on any available support: it covers fences, climbs over walls, reaches into trees, and quickly adorns facades, arbors, and pergolas. It pairs well with Virginia creeper, large mountain clematis, or wisterias.  

The grapes of this vine can be eaten as table fruit after being exposed to frost, but they can also be used for jam, jelly, pastries, and wine. The frost grape provides food for bees and birds that nest in its vegetation, as well as for the red fox, which does not disdain the fallen grapes on the ground.