I like where you were going with it, with the tree in the foreground and the reflection. They are tricky because the firework is so bright and everything else is very dark. You need to choke off the light by using your lowest ISO and stop the lens down pretty hard like f8-f16 or maybe even more, then you slow the shutter down to 5-10 sec. The fire burns quick so it hopefully you won't clip the highlights too bad and the long shutter gives more motion and gives the dark a chance to catch up with the bright. Even then you still have to do some work in post to pull the highlights back and the shadows up.