If you're growing for showing, then netting, but for house/garden use, then canes are fine - they will twine their tendrils round the canes and each other for support. A wigwam of ordinary canes will do fine, it's what I use, sometimes stringing garden twine between the canes, but they don't really need it. I have some of those silver coloured twisty supports that were donated to me, and the look quite good growing up them - the blue sweet peas this year.
Left to their own devices, they will grow to 8 - 9 ft in good soil, but you can just pinch out the tops; as well as controlling the height, this gives lots of side-shoots to give more flowers.