Measure up each trellis leg one-third to the top. Mark this spot on each leg with a pencil.
Screw a small eye hook into the front and the back side of the leg at the pencil mark. Repeat for each leg.
Loop and tie a wire or length of twine through each eye hook. Tie the other end of each length of wire to a 6- to 8-inch stake.
Hammer the stakes into the ground. Pull the wires taut before hammering the stake. The wires stretching out from each side of the trellis stabilize the trellis so it can't fall forward or backward.