Mark the canes each year to indicate what age they are. Use a different colored tape for each year. Look for the two-year-old canes, which are the canes that produce the berries. Do not completely cut back the one-year-old canes since they will produce fruit next year. Leave four to five canes per bush.
Prune black raspberry canes for the first time of the year in mid-March. Cut back the new branches so that they are about 12 inches tall.
Wait for the canes to reach a height of 24 inches, which should happen between May and July. Use your pruning shears to trim two to three inches off each cane. Do this to new canes as they grow, but remember to only trim each cane one time at this point.
Remove the canes that produced fruit this year after the harvest is completed. Use the pruning shears to cut those canes down to the ground since they are dead and will no longer produce fruit.