May,
There are some varieties that seldom bloom, even when in full sun. Mine are in full sun and bloom every year, however, I have a tiny patch planted in the shade of a Maple that seldom bloom. Full sun makes a difference on blooming with nearly all varieties.
Side note: The Colonials sent Sunchokes all over the world from the early 1600s on and today there are over 400 recognized varieties. A friend in Tasmania remembers her mother cooking them when she was a child. They'll nearly all handle zones 3 through 8 but there are some that take zone 2. Those are usually found in northern Canada and northern European countries.
I had one variety that grew 12'+ tall and spread way over 4' underground. They were a white/tan skinned smooth tuber like carrots in size and shape. They were, however so obnoxiously turnipy/herbal flavored that one tuber chunked into a large soup pot nearly overpowered the soup. I got rid of them. They do not all taste alike! I've collected mine locally in west-central PA, near the heart of their native range and where people have these tall, beautiful, yellow flowers in their yards and flower gardens that they don't have a clue what they've actually got.
It's best to find varieties that are known to grow well in your climate, but it's also OK to try any you can get your hands on. There are varieties that mature in just over 100 days and others that take over 150 days. I only have two types now and they mature three weeks apart. That gives us a tad bit more time in the fall to harvest. Some types spread tubers over 6' and others that spread only around 16" and clump in an easy to pull gob!
The early type seldom has flowers that last until first frost, but the second type lasts well after first frost and the flowers and leaves are hard frost hardy, barely wilting. I do not harvest based on frost but only when the tops die and fully dry, just like harvesting potatoes. Potatoes and Sunchokes can be very bitter if harvested too early.
