Planted our trees last spring, and they tripled in size. When fall came, they dropped all their leaves and their branches. I have tall sticks, we had temperatures in high 20s for about 4 days. Did that kill my trees or do they normally drop everything?
Jacaranda Trees can suffer damage when exposed to temperatures below 26 degrees F.
You can check the tree by bending the branches. Do they snap off or bend?
Scratch the bark. Is it green underneath?
The roots may be unharmed and you can give the tree time to see if it can recover.
Here are some links to help you.