|
|
Vines that have not been grafted onto American rootstocks are more resistant to drought. Wineries in Spain and Chile in particular are reverting to ungrafted vines where possible. The director of Numanthia in Toro in Spain, for example, reported in an interview with the British trade magazine drinksbusiness that his old ungrafted Tempranillo vines had produced good yields of high-quality grapes this year with extreme heat and a lack of rainfall, while in other regions the same grape variety suffered from drought stress, which affected quantity and quality. Quinta da Noval in Portugal's Douro region is planning to produce a Quinta do Noval Nacional Vintage Port from the Nacional vineyard with ungrafted autochthonous varieties, despite the 70 per cent reduction in rainfall.
Michel Friou, winemaker of Almaviva in Chile, had found that his ungrafted vines also coped better with the increasingly drier conditions in the Maipo Valley than those grafted on rootstocks. The technical director of Concha y Toro, Marcelo Papa, even bottles his own wine from such Cabernet Sauvignon vines under the name "Heritage" because they provided "Unique character and high quality".
He pointed out that ungrafted Cabernet vines have particularly deep roots, but this is not an advantage everywhere. "In an area like Maipo, where the water table is around 100 metres below the surface, the roots have to go deep to find a stable amount of water in the soil. In Bordeaux, it's the opposite. There, you should perhaps choose a rootstock that roots horizontally", because there the groundwater is only a few metres deep. Not all ungrafted vines would root deeper than those grafted onto rootstocks. This depends on the variety. Merlot, for example, has such a "sluggish root system that it is a disaster when ungrafted in Chile - it doesn't get enough soil water and you get sultanas, so Merlot grows best on rootstock".
(al / source: drinksbusiness; photo: Lupersböck)
More on the topic:
Spain's oldest Tempranillo vines in danger