Vine Planting: The Choice of Rootstock

Planting vines is a crucial and almost decisive step in the success and evolution of a vineyard. The choice of rootstock and grape variety are among the first considerations for the winegrower when planting and will affect them for several decades. Currently, rootstocks are used to plant vines. These rootstocks not only protect the plant but also play an important role in its behavior and capabilities throughout its life cycle.

Rootstocks in our vineyards

Vine stocks can be planted directly in the soil without a rootstock, referred to as “ungrafted vines.” A few winegrowers have ventured into planting ungrafted vines in recent years, such as Domaine Charles Joguet in Chinon with their Cabernet Francs or Henry Marionnet, a pioneer in this field. However, this remains very rare, as since the phylloxera crisis, most grape varieties are planted with rootstocks. But why?

The aphid known as phylloxera appeared in French and European vineyards as early as 1863. The European vine species Vitis vinifera, which produces all the well-known grape varieties used for making wine, cannot withstand the insect’s bites and dies within 2-3 years. The insect spreads rapidly through the soil, and within about ten years, the French vineyards, as well as a significant part of European vineyards, were destroyed. Research was conducted to revive the French wine industry, which was economically very important at the time.

The solution came from other vine species, such as Vitis vinifera. It was discovered that American vines (Vitis rupestris, Vitis riparia, Vitis berlandieri, Vitis labrusca, etc.) were highly resistant to phylloxera but were not suitable for wine production due to their poor organoleptic qualities. By grafting European Vitis vinifera onto an American rootstock (the root part), the expression of European grape varieties was preserved while ensuring the vine’s resistance to this predator.

Vine grafting is mostly done in nurseries so that winegrowers can buy already grafted vine plants. There are several grafting techniques, but the most common is the “omega graft,” a method used to fuse the scion and rootstock, done outside the vineyard. This method is widely used in 95% of French vineyards

Machines for assembling grafts

This “puzzle” technique, where two vine parts are joined, is done on a table using two machines—one to trim the ends and the other to assemble them. After joining the two ends, wax is applied to secure the graft, a process known as “paraffining.” The vines are nurtured until a callus forms between the scion and rootstock.

The winegrower selects a rootstock based on the grape variety, soil type, and environmental conditions of their vineyard.

The different types of rootstocks

There are several dozen authorized rootstocks in France. Each one has different characteristics due to the numerous cross-breeding experiments conducted between different vine species.

There are four main criteria for choosing a rootstock:

1. It must be adapted to the geological characteristics of the vineyard: more or less calcareous, more or less acidic, presence of metals, sodium chloride, etc.
2. It must adapt to the climatic conditions, especially temperature. In colder regions, an early rootstock is preferred as it accelerates the vine’s growth cycle.
3. It must be resistant to pests (phylloxera, nematodes) and adjust to the soil’s water balance (drought or excessive moisture).
4. It must be suited to the type of production sought (managing vigor, production volume, or yield limitation).

American vines live in different climatic and soil conditions compared to Europe.
Thanks to their original environment, they have developed various abilities, especially resistance to phylloxera, but also other properties depending on their planting zone of origin.

The three most commonly used species are all resistant to phylloxera but have specific characteristics:

• Vitis riparia: very early species but not resistant to water stress. It is best suited for humid and cool areas.
• Vitis rupestris: not resistant to limestone but resistant to drought. It is preferred in hot, dry areas with alluvial soils.
• Vitis berlandieri: slow-growing species but resistant to limestone. It adapts to many European soils due to its tolerance to limestone but needs to be combined with early grape varieties.

Cross-breeding is carried out between these three species as well as with the European species Vitis vinifera, which is resistant to limestone and salt in the soil and is earlier than Vitis berlandieri. Hybrid rootstocks result from cross-breeding between multiple species.

It is worth noting that at the end of the 18th century, cross-breeding was also carried out between American and French grape varieties to address the phylloxera crisis. These varieties are highly resistant and require little maintenance, and are known as “direct producer hybrids.” In response to the high production demands of the time, these varieties were used by French farmers to produce table wines. The very poor quality of these wines and the resulting overproduction crisis led France to ban them in 1935, with incentives for uprooting and financial penalties for producing wine from hybrids.

Discover the wine and spirits training catalog offered by WiSP and become an expert in the field: world-class WSET and Wine Scholar Guild courses to become a wine and spirits expert