What is the advantage of using a rootstock?
The primary objective of a rootstock is to prevent phylloxera. However, it has many other major benefits including its ability to adapt to the soil profile and the desired production style. For example, the rootstock can be used to control the vines' vigor and therefore the yield. It can also have characteristics which make it well-suited to the surrounding environment such as humidity or drought, or indeed, it can be compatible with the level of active limestone in the soil. The right choice of rootstock will make it possible to get the best out of any soil type.
When a Vitis vinifera vine is planted without a rootstock, we refer to it as a franc de pied or ungrafted vine. This implies that there is no mixing of species.