If it still does not flower this year - and mine are only recently doing so, very late - it wil respond to some pruning and care this coming winter. When we get to autumn, cut the whole plant to about half its current height, and give it a nice deep mulch around the base. Next Spring prune it as hard as you like, down to 6 inches above the ground is ok, and feed it - it should delight you with flowers and butterflies after that.
I have a reddish/purple hybrid that refuses to flower until it is at least 12 foot tall, even though I cut it down every year, so you will do it no harm by doing this.
There is a disused site - it used to be a brewery - near where I live, and it is a forest of heavily flowering wild buddleia - with clouds of butterflies. Willl be interesting to see if it all flowers next year - unless of course the developers have got at it by then.