im sorry i cant help you but perhaps if you ask someone like bamboo who is a plantspersen youl have some better luck with your question .

It's a bit risky. The usual procedure with Callistemon is to tip or light prune after the flowers fade, when you cut directly behind the spent flower head, removing that together with any new growth at the tip beyond it. You have not done this, presumably, so now you've ended up with an unproductive plant. I'm assuming its in the ground - if its in a pot, then it may well need repotting, and that might solve your problem.
In Australia, when plants get like yours, they cut them to the ground, which is what a bush fire would do, and then give them a good feed. Some survive this, some don't - those that do thrive and respond well. However, this would best have been done during April to give the plant time to recover before winter sets in.

I've got 2 bottlebrushes in the garden I've recently moved to that sound in similar condition, there's a couple of photos in my "My new garden" blog.

We're in the process of cutting them back fairly hard at the moment, although there is some new growth appearing both from the base and higher up on a few of the older stems that we're trying to avoid cutting off! I hope we're doing the right thing for it given there isn't much we can do now about what's happened previously. I'd be interested to hear what you do and how it works out :)

Bamboo - What sort of food would be best to give it now if we are having to prune it hard at this time of year?

Thanks everyone, think I'll give it a good prune and feed and see what happens.