What causes Bottle brush tree to turn brown a few weeks after planting. Was watered 3-5times a week....but when planted the burlap was left on it and it was aprox. 6 inches above the ground. The landscaper brought in fill about 1 month later to cover it
Daily watering for the first 2 weeks is needed. They you can cut back. 3 to 4 inches of hardwood mulch will help with moisture retention but make sure the mulch is back 6 inches from the trunk.
I suspect your tree is not getting enough water.
We do recommend the removal of burlap from the tree roots.
These links have more information.