A Comparison of Blackberry Cultivars for a High-elevation Arid Climate

Blackberries are only marginally hardy to the high-elevation valleys of the Intermountain West, but growers are interested in blackberries as a diversification opportunity to capitalize on increased interest in local produce.  A planting was established in 2006 at the Utah State University research farm in Kaysville, Utah (41.01 N latitude, 1330 m elevation) to evaluate 21 blackberry cultivars for suitability to commercial production in the region.  Each cultivar was planted in at least two replicate plots with 2 to 3 plants per plot.  Winter cane injury was visually evaluated each spring, and ripe fruit harvested to determine yield, production season, and fruit size. The winters from 2008 to 2012 presented a wide contrast in winter conditions that provided a good test for hardiness. Except for the two fall-bearing cultivars, yield was closely correlated with winter cane survival.  Illini Hardy consistently had the highest winter survival.  Among the thornless semi-erect types, ‘Chester’ showed the highest winter survival followed by Triple Crown and Hull.  Triple Crown had the highest average yields.  Among the erect types, Apache, Arapaho and Navajo showed the best winter survival and most consistent yields, while Kiowa had the lowest winter survival and yields.  None of the trailing types had adequate winter survival or yields to be recommended.  Semi-erect types and the more cold-hardy erect types are recommended for the Intermountain West.