Blueberry, in case you run out of growing tubers, I can chip some in, we have them growing in the community garden and there's always a few spare ones.
I'm rather late into this thread. Any chance you still have Yacon tubers everywhere.
We live in Nelson, little frost, and would love to give this plant a go.
Happy to pay courier post or what ever for shipping.
I have been growing yacons that came from Blueberry some years ago. Mine aren't quite ready to dig yet, but I live within commute distance to you so if Blueberry doesn't answer, send me a pm in a few weeks time and we may be able to arrange something.