I just planted it this spring, I'm just getting into plants and shrubs so I've got alot to learn but I wanted to cry when I seen what had happened to my lilac especially since I paid $25 for it. I think I will do as you suggest and bind it and see if it heals. I was afraid of rooting, I was thinking if it did in fact root It wouldn't be the season to plant it unless I kept it going all winter.
Thanks Again! I'll cross my fingers.
You say that the main stem is damaged. Are there other stems? If so you may be better off just removing the damaged portion. How long has the shrub been planted and do you consider it to be well established. The reason I ask is that the Lilacs that I am familiar with sucker from the base pretty freely and yours will probably produce a new shoot, or several, in the spring if it is healthy.
I am doubtful about the chances of getting it to root this time of year. There is also the issue of whether Lilacs root better from new or old growth. They sucker so freely I have never tried to root cuttings.
You can try to bind the stem and brace it, it may heal enough to sustain the shrub until new growth appears.