Blackberries grow into bushes 3 to 4 feet tall and wide. The roots of the plant are perennial, but the top is biennial; that is, a branch that comes up this spring will not fruit until next year, and after fruiting it will die. To maximize your berry harvest, you need to prune the shrub correctly.

How tall should a blackberry trellis be?

After setting, the posts should be about 6 feet tall. Either two- or three-wire trellis systems are generally used. A two-wire trellis system is usually adequate, with the top wire at approximately 5 to 6 feet above the ground and the bottom wire at approximately 31⁄2 feet above the ground.

Do you need a trellis for blackberries?

Blackberries require trellising to support the canes, keep fruit off the ground and protect canes from wind damage. The exception is ornamental, dwarf, everbearing, erect cultivars; these also produce much lower yields (see “Harvest,” page 13).