Growing Berries in Your Backyard
Figure 16.2. See more detail in pdf linked, below.
Trailing blackberries require a trellis system to support the fruiting canes. Erect blackberries grow without support, but trellises will keep the planting neater and make harvest easier. Set heavy posts (4" by 4" by 8' long), in concrete, at least 2 feet into the ground at each end of the row. Set lighter posts (2" by 2" grape stakes) about 15 feet apart in the row. 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. Some gardeners use a three-wire system, spacing the wires at 6 feet, 4 feet, and 2 feet above the ground. Strong galvanized wire (Number 10 or 12) should be used for strength and durability. The trellis should be installed at planting time.