Form the frame of the trellis by setting two of the 8-foot bamboo poles parallel to each other about 5.5 feet apart. Lay two of the 6-foot poles across the 8-foot sections about 6 inches from the ends. This will form a rectangular-shape frame. Cut four pieces of twine about 12 inches long and wrap the poles where they meet in a crisscrossed pattern and tie twine in a simple knot. Trim any excess twine with scissors.
Flip the frame over and set the five remaining 8-foot sections across the 6 foot poles so that they are spaced equally between the parallel 8-foot sides of the frame. Cut 10 sections of twine 12 inches long and loosely tie all 10 ends to the frame.
Slide the seven remaining 6-foot bamboo poles into place by weaving them above and below the 8-foot poles and positioning them so they are equally spaced between the parallel-6 foot sides of the frame. Cut 14 sections of twine 12 inches long. Then tie each end tightly to the frame, again wrapping in a crisscrossed pattern for stability. Tighten the loose twine on the 8-foot poles, wrap in crisscrossed pattern and trim excess.
Cut several 12-inch lengths of twine, wrap and knot poles in each place where they intersect. This will make the trellis sturdy enough for even very heavy vines.
Prop trellis against fence and weave vines between poles to promote climbing.