Q.cutting bottlebrush
If I cut a bottle brush right back to a large single trunk, will it survive? We have a large, but spindly, bottlebrush that we would like to become fuller to look like a bush rather than a small tree but I’m worried if I cut it right back to the trunk that it will not survive.

Early spring would be the time to prune your Bottlebrush.
Here is a link with more information.
https://www.gardeningknowhow.com/ornamental/shrubs/bottlebrush/pruning-bottlebrush-plants.htm