I bought two last year and after a short time a fungus grew on the leaves.
I thought that they would begin to show signs of flowering by now but aren't doing anything.
Are they dead?
I would expect to see developing buds on any willow now. Flower and/or leaf.
What did they look like at the end of last season?
If you scratch a branch with your finger nail do you see green? If not they're probably dead.
These things are grafted onto a root stock and, in my experience, short lived. They are willows so require a lot of water. Mine curled up, despite being well watered, after just 5 or 6 years. A friend's died after 7.
In the end I was pleased mine died as its grafted head grew its branches far too long for the root stock stem and I was forever pruning the thing to stop the branches swamping ground cover and other plants.
I dug mine out a couple of weeks ago. Got very fed up with it taking up so much room in a very small bed outside my bedroom window.
They don't offer much after the catkins have gone do they There was one in a prominent position in one of my work gardens
This one didn't even grace us with that many catkins.
Another plant the previous owners planted which I've now removed.