My 10 year old Bottle Brush Tree looks dead. It has brown leaves in September. I live in Las Vegas.
Bottle Brush Tree
Certified GKH Gardening Expert
I would definitely be mindful of the pH of the soil. Dolomitic lime will help keep the soil buffered, and prevent a calcium/magnesium deficiency. Here is an article that will help further: https://www.gardeningknowhow.com/ornamental/shrubs/bottlebrush/growing-bottlebrush-plants.htm