My SIL on Long Island NY planted one that did not flower for over 10 years, until she hired someone to prune it out of the trees and off the telephone wires. It flowered heavily the following year!
I prune mine hard to keep to a standard/tree from it blooms well for me.

if it isnt old enough it wont bloom. it can take up to 7 or more years before it blooms. pruning it may help it but i have a friend who swears she has to treat her white one different then the purple. i have 2 purples one is blooming its head off while the other is growing leaves. age plays a big part.

the white ones here are just now flowering as its like 80 out during the day. also maybe giving it some bloom boost might help. dont give up on it just yet.

Moonvine - how does your friend treat her white wisteria different than the purple?
My white one has rampant growth (like my purple ones) but no indication of any flowers. I believe that it is old enough, as I purchased it from a nursery about 6 years ago and it has almost covered a 40 foot pine tree.
I cut off about 1/3 of the large thick vines - perhaps this will get it's attention.

did you perchance grow the wisteria from seed? I have read that from-seed plants will never bloom?