For the last couple of years I've been lucky enough to obtain pre-release samples of "Fiorella", a recently bred fast-maturing variety of yacon from Paul at Yakon.co.uk
It's the variety that I've used in the 'All-tuber-mound', and 'Not the Three Sisters' planting schemes, and such is the superiority of Fiorella that I've now abandoned the white variety that I grew previously.
Here are a few of the edible tubers...
And it makes a very handsome border plant...
This link will take you directly to the on-line ordering:
(not to be confused with yacon.co.uk which is a yacon syrup importer).