Q.I have a 48 year old bottle brush that only has leaves on the outer parts
It has always been a lovely tree. It has never been pruned or had any special treatment, just more or less left to itself. Is there anything can be done for it.
Certified GKH Gardening Expert
Typically these need restorative pruning to keep them healthy for as long as possible. Over time it will lose its vigor and start to do what you are seeing now. The only thing to do now is to have a tree trimming professional come out and help you prune a tree of that size, as this can be very dangerous without the proper equipment.
This article will give you more information: https://www.gardeningknowhow.com/ornamental/shrubs/bottlebrush/pruning-bottlebrush-plants.htm