Answer: Bismarck is located on the border of USDA Hardiness Zones 3 and, so I'm afraid you won't have good success with blackberries. Most rated hardy only to USDA Zone 5 or Zone 6.
I suggest you stick with hardier fruits, such as raspberries and elderberries. Currents and gooseberries are also hardy; however, because they are alternate hosts for a disease of white pines, some states prohibit their culture. Check with your department of agriculture before planting. Jostaberries are another member of the Ribes family and are reputed to be resistant to this disease.
You might enjoy checking out the offerings of St. Lawrence Nurseries (ph no. 315-265-6739; web address: http://www.sln.potsdam.ny.us) They carry a wide variety of edible plants hardy to Zone 3.
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