As relatives of sunflowers, you can see why Jerusalem artichokes are called 'sunchokes' in the US.
We are trying a batch in the garden. By mistake, I pulled out a root. The choke was tiny, scarcely bigger in girth and length of my little finger. They need more time. Zia told me to cut off the flower heads:
'Too much energy is going into those and you need it all in the tubers'.
I shoved the untidy but cheery blossoms into a vase.
This is a perennial plant that originally comes from the New World, cultivated by native Americans. It isn't as starchy as it tastes, containing inulin. This is a good food for diabetics. The problem is the resulting wind, but if combined with cumin seeds, say in a soup or roasted with olive oil, that should help with the 'fartichokes'.