The roots of a grapevine. More often than not, european wine grape vines, or vitis vinifera, are grafted onto american grapevine roots, commonly vitis rupestris (from the latin "lives on cliffs or rocks") or riparia ("of riverbanks.") In the 19th century, an american root eating aphid known as phylloxera made its way to europe via an English botanist's garden in the Rhone valley, and devastated vineyards across the continent. The wine industry was on the brink of collapse until it began grafting vitis vinifera onto the roots of aphid resistant american grapevines. It’s hard to say how an american rootstock affects vitis vinifera grapes and the wines they become, but we know it affects their vigor and the way they ripen, and different rootstocks are better suited for different terroirs.