These vines take several years to develop wood that is mature enough to bloom.
Patience is recommended. Young plants grown from seedlings may take 5 to 9 years
to produce their first flowers.

A vine allowed to grow wildly and left un-pruned, or one that is over-fertilized will take much longer to flower than one that is properly pruned and fertilized.
To produce a full crop of flowers wisteria need lean soil, full sunshine and infrequent watering. Too much shade, water or fertilizer will keep them in a vegetative state and they will not set buds.
Pruning too much, or pruning in winter or spring can remove buds already formed. If you need to prune do it in late summer or fall. In summer train the long new growth in the direction you want it to grow. To encourage the growth of flower spurs cut unwanted shoots back to about a foot. In late fall cut these side shoots back again, leaving only two or three buds on each one.