Hold the trellis against the wire fence in the desired location, ideally in the middle of two adjacent posts for a uniform appearance. Although you can mount the trellis to the fence going lengthwise, position it standing up for an aesthetically pleasing arrangement.
Lift the trellis 2 to 3 inches off the soil line to prevent rot. Attach a top corner of the trellis to the fence with tie wire. Wind a length of tie wire through the corner of the lattice trellis and corresponding section of the fence several times. Tighten the wire with pliers and clip excess off with cutters.
Walk to the opposite corner of the trellis to attach it to the fence. Ensure the top of the trellis is level and its base is 3 inches above the soil line. Repeat the process of securing its other top corner to the corresponding section of the wire fence with wire.
Attach the trellis to the fence every 12 to 18 inches along its width to keep it from shifting during strong winds. Also, secure the trellis to the fence at a few more spots, such as the middle and lower corners, to provide added stability.