Cold Hardiness and Survival of Interspecific Vitis Hybrids

Cold hardiness and survival of wine grapes in two locations in North Dakota was determined using differential thermal analysis for five cultivars in 2020 and six cultivars from 2020-2021. Phenological data was collected during the growing season of 2020. Phenological data showed that cultivars broke bud early in the season and matured before the first fall frost. In 2020, cultivars at Red Trail Vineyard were hardier than those at the North Dakota State University Horticulture Research Station and ?King of the North? exhibited greatest hardiness, while ?Frontenac? and ?Frontenac gris? exhibited lowest hardiness. Across both locations, ?King of the North? proved to be the most cold hardy cultivar. Unpredictable minimum temperatures during dormancy, subsequent winter injury and herbicide drift all influenced bud cold hardiness, vine recovery, and survival. These results suggest that when growing wine grapes in North Dakota, cultivar selection and vineyard placement are critical factors in sustainable production