Cinnamon is a mild fungicide and bactericide, but - as has been stated - should only be used on the wound, itself, because it is also a tremendous desiccant. If left all over the roots as it was, the likelihood of it ever growing new roots was pretty slim; the existing ones would die, and any new ones emerging have a high likelihood of contact with the cinnamon and desiccating to death.

If you're looking to stimulate root growth, use a hormone-containing product intended for that. KelpMax is one of the best available.