The behemoth still stands but this one had to be removed.

Tiny roots for such a huge plant!

It seems to be a taproot, Gillian. I planted the beans in Jiffy 7's and they grew in a spiral. once in the ground they anchored the plant really well as they all stood up well until we had the hurricane residue... was pretty ruthless when I removed the plant and just sank a spade all the way around...cutting the roots... the stalk was so lignous that I would have had to use a saw and since it's supposed to be poisonous I didn't want to spray dust from the sawing around the plant...so I cut the side roots and pulled it up! As I said, next year I'll have a better idea where to place them.