Why won't my wisteria flower

You need to tell us a bit more. How old is it? Where is it growing? What direction does it face?

Position sounds fine and the plant healthy so, unless you bought it in flower, it's likely to be too young. Some wisterias are seed grown, and they can take up to seven years to flower.

The other point is have you pruned it correctly - look here for instructions:

http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=242

I planted two expensive grafted hybrids three years ago, and they still don't look as if they are going to flower this year! 

I have let them grow to fill the available space.. This year I am going to cut back all but the essential growth, and will prune these back in July to encourage flower bud development next year.

It may well be the pruning ... mine is about 3 years old ... I've never had flowers,  but last year I looked at a couple of videos about pruning (when and how).  I followed these rules and this year I've had loads of flower buds !

Thats the good news,  the bad news is that with all this rain,  the buds got completely waterlogged and they've just rotted and dropped off.

Still,  better luck next time !

Si I think the answer could well be to prune according to the YouTube pruning instructions !

Chris

hi ive had my wisteria  about 4 years and it didnt flower untill i gave it a hard pruning now it has got lots of flower heads on it  i think if im not mistaken you prune it twice once in the spring and again in the autumn  thats what i do and it works

In Boston market yesterday I saw some wisteria "Amethyst Falls" that were only 70cm tall, and they had several big flower buds.  I am sure one of mine is the same variety!  

So, out with the secateurs in June, cut out all but the strongest stems, and cut the remaining ones back by half. Hopefully I'll see buds developing next February, and I'll cut back again to fatten them up. 

Grafted plants are supposed to be the best and in flower when you buy but when I got mine I would have needed a second mortgage to buy what I wanted so went for a small potted 'whip'.  I had a new garden at the time so there was nothing in it so all plants purchsed where small.  That wisteria took over ten years to produce any flowers at all!  Sadly, at that time I didn't have any pruning information so just stopped it looking sad & weeping willow like!  Once it started flowering it was lovely but not the blue I expected, more of a lilac color.   I have now moved house and didn't have the heart to did it up as it had spent so much time 'settling'.  I am now trying again with some bare root plants and so far they are still like dead twigs!