Grown from seed Wisteria can take many years and the myth that Wisteria is difficult to grow persists because it does not flower as a young plant, and needs to be managed.
Fortunately there are many good suppliers of 1,2 and 3 year grafted plants which reduce your waiting time – and you can always pay a bit more and have a more mature flowering plant.
You need to source a supplier carefully, as Wisteria (like many other plants), are notoriously mislabeled.
They also love to be cut back, especially the new tendrils that grow throughout the summer. The flowers form best on short branches, so if cut back to 3 leaves or so you are encouraging the plant to flower.
A mistake people often make is to leave a wisteria to it’s own devices – in which case it just grows and grows and becomes untidy and straggly and will take far longer to flower! They really do love to be pruned regularly….