Please bear with an inexpert gardener!
We bought some blueberry bushes a few years ago, and when we pruned them, we stuck some of the prunings in water to see what would happen, and they grew! So now we have half a dozen large blueberrry bushes.
The only problem is that none of them ever fruit - they just produce catkins.
A quick google search confirms that blueberries don't produce catkins. Mind you, a quick google search also confirms that bumblebees can't fly.
Anyway, can somebody please tell me what We've done wrong?

Some photos of the bushes and catkins are attached.