Lay two pieces of bamboo on a flat surface, so one piece is pointing away from your body. Lay the other piece on top of it at a right angle so that both pieces cross about 12 inches from each end. This will be a corner of the trellis. Cut a piece of lashing cord 6 feet long. Drop it over the top of the vertical piece just below the horizontal cane. Adjust it so about 3 feet hang down on each side.
Wrap both pieces under the horizontal cane, on either side of the vertical cane. Cross them on top of the vertical cane, on the opposite side, and pull them tight. They should not be crossed underneath. Bring both ends back under the horizontal cane towards you, not crossing them, and cross on top of the vertical cane. Pull them tight. Repeat three times. Cross the lashing cord under the vertical cane, rather than on top, when you make your final cross, on the side nearest you.
Wrap the cords over top of the horizontal cane, with one cord on each side of the horizontal cane, cross the cords underneath the vertical cane on the opposite side of the horizontal cane. Pull the cords tight. Wrap them back toward you, over the top of the horizontal cane, crossing them under the vertical can. Repeat two times, pulling the cords tight after each cross.
Tie the cords together on the last cross underneath the vertical cane on the side nearest you. Pull the cords very tight. Tie the cords again to create a knot. Trim the excess cord.