According to the EU regulation, member states must classify the wine grape varieties that may be planted or grafted on their territory for the purpose of wine production. These must belong to the European species Vitis vinifera or come from a cross between this species and other species of the genus Vitis (e.g. the Asian Vitis amurensis or the American Vitis labrusca). However, six varieties of vine are prohibited although they meet these conditions. These are Clinton, Herbemont, Isabella, Jacquez, Noah and Othello. Why exactly these six have historical reasons, which even today nobody knows or can explain officially (one of the secrets of EU laws). Although they are American hybrids, there are countless others that are allowed to be grown. If varieties are deleted from the classification, the areas concerned must be grubbed up within 15 years of their deletion (except for areas for domestic use by winegrowers).