It will grow a new leader if you contain the lower growth. I would shorten most of any trunk growth to about 2 inches for the next couple of years. When the leader is again growing well I would then remove the trunk growth to about 1/4 inch stubs. Doing this routine should help increase the girth of the trunk and make for a more wind resistant tree. Al

How awful! I'm sorry someone did that to your tree.

We had a few of our bottle brushes mowed to the ground a couple years ago and they are all growing healthily and have gotten over 5' tall in the time since the 'crime.' We are just letting them grow in a bush form, but I think they would be more than vigorous enough to train into a tree form if we wanted to. I would follow calistoga's advice and add to it just be patient, it's hard but a lot of times the best thing for an injured plant is to give it some time to grow.

Good luck!

If your tree is growing next to a public sidewalk, you might consider moving it. My experience has been that passersbye are apt to want to take home a part of a plant they like.

Thank you all so much! If only everyone loved trees and gardens as much as we do
And yes - I am moving the plant away from the sidewalk. I wouldn't have minded if someone cut off a side branch cause they liked it - but this was just broken in half and left hanging.
Anyway - thanks again