Did you scratch the bark to see if it's alive underneith? If it is it's just slow to come back from the cold winter we had.

Any suggestions? We had an unusually cold winter this year with 6 inches of snow in February. I have 2 bottle brush trees in my front yard that are brown all over & look dead. There is some new green sprouts coming out now but I was wondering if I need to cut back the brown limbs or just leave them? Some of the new growth is actually on the brown limbs. They look awful.

This link states that Bottle Brush are shrubs that can be trained to be small trees , around 15 feet .
They do well in Zones 9 to 11 .
If planted in a wet area , they often have fungal problems .
This says keep high and dry and in a warmer climate .

Here is a link that might be useful: Callistemon citrinus: Red Bottlebrush