Flower bud and shoot hardiness of southern highbush blueberry cultivars

The southern highbush blueberry (Vaccinium spp.) cvs. 'Blue Ridge', 'Cape Fear' 'Cooper', 'Georgiagem', 'Gulf Coast' and 'O'Neal', and selections A-109 and G-816, the rabbiteye (V. ashei Reade) cv. 'Climax' and the northern highbush (V. corymbosum L.) cvs. 'Bluecrop' and 'Sierra' were evaluated in December 1993 and January and February 1991 for shoot and flower bud damage following exposure to 0, -5, -10, -15, -20, -25 and -30C in a programmable freezer. All cultivars were hardier than 'Climax at all sample dales. Hardiness among several southern highbush clones was similar to that for northern highbush at several dates and temperatures. The hardier southern highbush clones were A-1O9, 'Blue Ridge' and 'Cape Fear'. 'Sierra' exhibited equal or greater hardiness than 'Blue-crop', depending on date of sampling and temperature.