Top-grafting is an ancestral and complex viticultural practice, a true demonstration of the winegrower's expertise. This technique involves changing the grape variety identity of an already established vine, while keeping its existing root system. It is essentially a "field graft", where the aerial part (the scion) is replaced by that of a new grape variety. This method is particularly relevant in the context of vineyard diversification or adaptation.

Why use top-grafting?

The reasons why a winegrower might choose to top-graft are manifold. The main one is undoubtedly the speed with which a grape variety can be changed, without having to uproot and replant the entire plot. While a new plantation requires several years before entering full production, top-grafting makes it possible to obtain a significant harvest of the new grape variety by the second year. This is a major advantage for responding to market trends, climatic hazards or the desire to experiment with new aromatic expressions.

Furthermore, top-grafting preserves the soil's balance and structure, avoiding the disruption associated with uprooting. The rootstock's root system, already well established, ensures better resistance to diseases and water stress, and provides the new grape variety with a solid foundation for its development.

When to top-graft vines?

The timing of top-grafting is crucial to the success of the operation. It is generally carried out in spring or early summer, when the vine's sap is fully flowing. This is the ideal moment for the scion to unite effectively with the rootstock. The period from May to July is often preferred, after bud burst and before veraison, as vegetative activity is intense. Top-grafting too late in the season can compromise the recovery and vigour of the new grape variety.

The key stages of top-grafting

Top-grafting is a delicate operation that requires precision and expertise. Here are the main stages typically followed:

• Preparing the rootstocks

  The existing vines are cut cleanly, usually a few dozen centimetres from the ground, or on a vine arm if one wishes to keep part of the original planting. The cut surface must be clean and smooth.

• Preparing the scions

  Vine shoots of the new grape variety, taken and stored since winter, are prepared. Each scion contains one or two buds and is cut into a bevel or a cleft, depending on the chosen grafting technique.

• Incisions and insertion

  An incision is made on the rootstock to accommodate the scion. The objective is to align the cambiums (growth-generating tissues) of both parts to facilitate healing.

• Tying and protection

  The scion is firmly secured to the rootstock using a tie (raffia, elastic) and the whole is coated with grafting wax to protect it from drying out and diseases.

• Post-grafting care

  Careful monitoring is necessary. Stakes are installed to support the young shoot, and any vegetative growth below the graft (suckers) must be removed to promote the growth of the new grape variety.

Specific equipment and tools

For successful top-grafting, the winegrower uses a set of specialised tools:

• Specific secateurs and saws for clean cuts.
• A very sharp grafting knife, to precisely prepare the scions.
• Grafting ties (elastics, raffia or biodegradable adhesive tapes) to hold the scion in place.
• Grafting wax, a protective paste that promotes healing and prevents infections.
• Stakes to guide the growth of young shoots.

A key to adaptation and diversity for the vineyard

Top-grafting, whether carried out in organic or conventional agriculture, is part of a vineyard adaptation approach. It provides valuable responsiveness to climatic changes, new regulations or market demands. This technique is environmentally neutral, and its effectiveness depends more on the grafter's expertise than on the farming method. On the scale of an estate like Château Cazebonne, top-grafting is a way to preserve biodiversity by introducing and testing new grape varieties or ancient varieties, without the heavy investment in time and resources of a complete uprooting and replanting.

At Château Cazebonne, we use top-grafting as part of our approach to promoting the forgotten grape varieties of Bordeaux. This technique allows us to reintroduce varieties to our land that had almost disappeared from the Bordeaux wine landscape, thereby helping to revive a heritage of inestimable wealth. Omega grafting enables such work, made possible thanks to the commitment and support of the many enthusiasts who have adopted our wines and share our vision. Explore the unique flavours of our wines online in our boutique. If you would like to learn more about this fascinating history, feel free to download the digital version of our book "Bordeaux, une histoire de cépages". Finally, to test your knowledge, take part in our oenological quizzes and discover the world of Château Cazebonne with a fun and educational perspective.