Training blackberry vines allows the vines to form supported growth rather than grow in a wild, unruly tangle, which is neither aesthetically pleasing nor beneficial to the plant. Different forms of blackberries require different training techniques. Identify your blackberry bush as either erect or trailing before learning how to train them. Erect varieties have thicker canes that arch upward, giving the vines some support. Pruning is the key to well-trained erect varieties. Trailing blackberries grow more in clumps along the ground and are not as self-supporting. They need trellises to prevent them from growing along the ground.
Plant erect varieties so that they will be self-supportive without the need for a trellis, like trailing varieties. Plant the erect varieties in rows, which will encourage the canes to form a network of supportive hedgerows.
Prune the erect canes to ensure tidy growth and structural support. Prune the vertical, non-fruit producing canes or "primocanes," after they are 75 cm (30 inches) high, during the summer. They will become the fruit producers in the next growing season.
After the bushes have finished producing fruit for the season, trim back the fruit producing lateral vines, or "floricanes," back to the central vertical cane.
Thin out the erect canes during the winter, removing weaker canes so that there are five canes per every foot of a row.
Drive a 2.4 m (8 foot) pole 60 cm (2 feet) into the ground at either end of a row of trailing blackberries using a post driver.
Install wire fencing stakes as supports every 1.5 m (5 feet) along the wire, if necessary.
String three lines of fencing wire between the end posts and support stakes, starting the lower string 90 cm (3 feet) from the ground and the second two 1.2 m and 1.5 m (4 feet and 5 feet) from the ground.
Train the established vertical primocanes to grow up through the wires, weaving in and out of the wires for support. Wrap fruit-bearing floricanes along the wires so they grow horizontally. Train new primocane growth to grow along the ground in its first, non-fruit bearing season, placing U-shaped wire stakes over the top of the canes to keep them in a line along the ground.