Contact an agriculture expert in your area. You might find a good advisor at your university agriculture department. Your state may have an extension department that may be able to direct you to a good source. If you can find an authority that deals specifically with growing black raspberries, so much the better.
Consult with that authority about which black raspberry plants will grow best in your area. Factors to consider include the type of soil where you live, the local climate, and the varieties of black raspberry that are available for purchase.
Visit area farms that grow berries. This will give you an idea of how healthy plantings should look. You can also talk to berry growers at the farms about cultivation tips, if you get the chance. Finally, you can actually taste different kinds of berries at most farms and select your favorite variety.
Shop for disease-free black raspberry plants. Check out quality nurseries. Berry farms that sell plants are also an option. According to the North Carolina Cooperative Extension Service, it is best to find plants that are tissue-cultivated, as they are certified to be free of viruses. In addition, the Extension Service warns against purchasing dormant black raspberry canes, as they may be disease-ridden.