Unheard of - young vines shattered by frost in Bordeaux

t the end of autumn, master pruner Massimo Giudici of Simonit & Sirch discovered grapevine trunks devastated by spring frosts in Cabernet-Sauvignon, Merlot and Petit Verdot vineyards located in Barsac and Pujols in southern Gironde. In blocks where overall temperatures plummeted to -6°C last April, young mixed plantings of 2 to 4 year-old vines have been displaying torn, splintered bark for months. Although he only witnessed this unusual damage on isolated mixed plantings in this part of Bordeaux, Giudici recalls seeing young vineyards in Italy affected across-the-board after the 2017 frosts. “There's nothing you can do”, said Giudici, who “decided to prune the three-year-old wood to regenerate the vines”.

“The wood has splintered, it’s no good, it has to be discarded”, confirms viticulture professor Alain Deloire from Montpellier Supagro. Judging from the pruning cuts (photo), the expert notes that “the spring frost affected the cambium cells, the most fragile cells in the wood, as they are meristematic cells. To cause this damage, temperatures must have dropped to -8-12°C, unless there was some weakening of the vine, caused by tillage tools for instance”.

This is the first time the viticulture professor has witnessed such damage in France. He points out that the frost did not cause necrosis on all the cambium, allowing phloem and bark to be produced, but not wood. “It's too damaged, and cannot be recovered: 30 to 80% of [sap] conduction has been lost, even though these are young vines in the process of getting established. If you continue on this cane, in 5 to 10 years the vine will be dead. You have to cut back below the splintered area”.