Poly-Natural: Cutting plastic waste under the vines
When you think about the sheer numbers of plastic ‘bread bag’ clips, metal twisty ties and cane clips littering vineyards, it is a worrying thought.
Stefano Vezza, an Italian grafter for the company, visited Martinborough late last year to demonstrate field grafting and explain why it is favoured by Worldwide Vineyards. “Hand grafting directly in the field promotes a high-quality weld which gives the vines a longer lifespan,” says Stefano, who demonstrated two types of field grafting to a group of winemakers gathered at Colombo Wines. “The main advantage of T-bud and chip bud grafting is that there is less likelihood of trunk disease and you have a 90% success rate.” The rate of trunk disease experienced with top grafting is eight to ten times lower than bench grafting, Stefano says. But the costs can be higher.
While in New Zealand, Stefano re-grafted On Giant’s Shoulders vines using chip bud grafting. The vineyard has a new owner, and winemaker Wilco Lam was keen to upgrade the vineyard using this gentle technique. Chip bud grafting takes the vine out of action for one year and means it can crop again the following year. Tying the vine during grafting is important to prevent wind from damaging the vine during the grafting process.
The benefits of grafting are multi-faceted and include the opportunity to change grape variety for experimentation purposes or to meet market demands. It also allows winemakers to change clonal selection and to rejuvenate aging vines.
However, grafting productive plants began as an intuitive response to grapevines for Worldwide Vineyard founders Paul and Marc Birebent, without any formal scientific training. Marc, now Managing Director, says grafting has been used “since antiquity” to harmonise the grape varieties of a plot or to improve fruiting. “Today, all vine plants are grafted in advance in a nursery. The term top-grafting refers to a new graft performed on the upper aerial part of the trunk, above the point of the original graft.” Another benefit of top grafting is that it has about three times less mortality rate than mechanical grafting on sensitive grape varieties, he says.
Stefano also visited Marlborough and Central Otago to discuss vineyard upscaling with winemakers in those regions. The visit was long overdue because of delays brought on by the global pandemic, says Worldwide Vineyards New Zealand representative, Simone Amorese, who owns Martinborough wine brand Equilibrium Makers. “We would love to have had him out sooner, if it hadn’t been for the pandemic.”
