Blackberry (Rubus subgenus Rubus Watson) production has potential to expand into North Dakota, but this will only occur with the evaluation of new cultivars and overwintering protection methods. Ten cultivars under four row cover treatments were evaluated for hardiness, vegetative growth, yield, and factors affecting fruit quality. Thermo-couples monitored air temperature under each treatment. Results indicate that the treatments differed in their ability to moderate winter air temperatures. Row covers had little effect on growth but differences were found between cultivars. The thermal blanket with corn stover resulted in significantly higher yield and more berries, but row covers did not affect fruit quality. Differences were also found between cultivars for fruit quantity and quality. Although row covers enabled fruit production after winter temperatures reached -30 °C, further research is recommended to improve winter protection techniques and identify suitable floricane blackberry cultivars for production in North Dakota.