We use half inch electrical conduit and nylon trellis.

Three 10 foot lengths of conduit and two 90 degree elbows. Sink two
of the pipes 3 or 4 feet onto the ground and connect the third pipe
in between with the trellis woven on the horizontal and vertical pipes.

The conduit never rusts and the nylon never rots. Ours has been up
for 7 years now.


Just a note, but nylon will deteriorate with intense enough UV exposure.
Doesn't last so long out here in southern AZ, but might be OK in northern
climes.