Well its a little late now - about the only pruning they need is deadheading as soon as the flowers fade, when you cut just behind the flower. There's usually a tuft of new leaf growth at the tip of the flower, and if you don't take the spent flowers and that new growth off, you get left with a bare bit on the stem as the new growth grows on, and the whole plant starts to look unkempt.

If yours is in this state, just cut it back till it looks better, though it is a little late - these shrubs aren't entirely hardy in the UK, so cutting back now will encourage new growth later which might not have time to harden off before winter sets in. If you're in a warmer region and your plant is in a sheltered spot, it has more chance of coping as the weather cools.

Thank you for replying. My bottlebrush has only just finished flowering last week, so possibly I have a late flowering one. It is fairly large and I have had it for 6 years but have just in the past, haphazardly trimmed some of it. Thanks again.

Local microclimate differences I expect, rather than a different variety - in London, they flower in May, though this year they were a little late due to the cold March/April. In other areas of the country, I notice they are later... but if yours has only just finished flowering, do it now...