For France, American Vines Still Mean Sour Grapes

French authorities have tried to outlaw hardy American hybrids for 87 years. But climate change and the natural wine movement are giving renegade winemakers a lift.

BEAUMONT, France — The vines were once demonized for causing madness and blindness, and had been banned decades ago. The French authorities, brandishing money and sanctions, nearly wiped them out. But there they were. On a hillside off a winding mountain road in a lost corner of southern France, the forbidden crop was thriving. Early one recent evening, Hervé Garnier inspected his field with relief. In a year when an April frost and disease have decimated France’s overall wine production, Mr. Garnier’s grapes — an American hybrid variety named jacquez, banned by the French government since 1934 — were already turning red. Barring an early-autumn cold snap, all was on track for a new vintage.