Vitis vinifera subsp. sylvestris is the wild and now rare ancestor of the Common Grape Vine. The only significant occurrence of this plant in Austria is in the Donau-Auen National Park. The Wild Grape may grow to heights of 30m. Its gorgeous autumn foliage makes it a seasonal eye-catcher in the riparian forest.
Description
The Wild Grape is a rare liana which may climb to heights of 20-30m. It has a densely-spreading rootstock and a woody trunk with brownish bark tending to peel in long fibres. The twigs are reddish- to yellowish-brown and normally hairless. Buds are dull, round to cone-shaped, from 6-7mm high; in particular the outermost bud scales are loosely fitting. The tendrils are lacking grips. Leaves are usually 5-lobed with a rounded or heart-shaped form and a noticeably upside-down V-shaped to closed petiole; the leaf stalk is hairless. Leaf margin is coarsely toothed; top of leaf is hairless while underside is woolly to nearly felt-like. A dioecious plant, its hermaphrodite (having both male and female organs) flowers appear in June and July in densely-gathered panicles which are pollinated by both insects and the wind. Flower petals are coadunate, or joined together (like little bonnets) and are dropped all at once early on. The fruit is elliptical in shape, bluish-black in colour, around 6mm long and sour to sweet tasting. The fruitheads are panicles (thus in botanical terms, not grapes). In general, the Wild Grape in all its parts is more delicate than the Common Grape Vine, Vitis vinifera.
Distribution
The Wild Grape is native to southern Central Europe, northern Africa and Asia Minor. Very rare in Austria and only occurring in Vienna and Lower Austria along the riparian forests of the Danube and March rivers. As a floral element of lowlands with mild climatic conditions, it may be found sporadically in the National Park at slightly higher elevations and on high river banks, whereby it prefers the left bank of the Danube.
Endangerment and Conservation Status
Vulnerable in Europe; currently found in only few riparian forests of the Upper Rhine Valley and thus critically endangered. Because its incidence is limited to Vienna and Lower Austria, the species is also classified as endangered in Austria.
Ecological Characteristics
The Wild Grape prefers colline or Pannonian Plain climate zones with warm, fresh to moderately dry soils which are not too chalky.
Special Characteristics
The Wild Grape formed the foundation for the first pre-Roman viticulture in Central Europe. This critically endangered species has disappeared at an increasing rate in the past several decades and thus deserves special protection. Its rarity makes it one of the absolute botanical highlights of the region. In the autumn, the Wild Grape is particularly easy to spot thanks to its flaming red fall foliage.