Wisty Wisteria

I've seen wisteria out in gardens elsewhere the past fortnight, but only now is my wisteria is out. I've a north facing garden, so that is probably the reason. I have the bush behind the shed:

For several years now I've trained it along the fence:

In the middle of last year I decided to let it continue up my neighbour's ash tree, as the wisteria flowers before the ash comes into leaf. It has reached half way up the tree, but no flowers this year. Next year I hope to have an ash tree full of bloom. Wisteria are supposed to be good for insects, but I've never seen any feeding from the flowers.