So, about a month ago, I planted a 3 gallon phyllostachys bambusoides in my back yard, intentionally digging deeper and much wider than needed to give the bamboo room to stretch, with about 8 cubic feet of compost/manure mixed in with the native soil.

Unfortunately, my dog eventually figured out how to get through the fence I erected and pulled one of my three culms out of the ground, proceeding then to chew off the point where the root meets the culm.

I have since watered the bamboo with a solution of 80 ppm IAA, hoping to aid its recovery and/or establishment. Sure enough, one of the culms that had previously shown little sign of life almost immediately began producing a large amount of foliage. Today, two weeks later, I found a bona-fide shoot popping out of the mulch. (On a side note, I am surprised how far from the original clump it is emerging... I am taking that as a good sign!)

On the vendor's website, and elsewhere on the web, everything I have read says it should not be shooting so soon. Could this be the result of the IAA (plant growth hormone)? Or is this how bamboo responds to trauma?

How will the damage done by my dog, who is now watched VERY closely whenever he is in the back yard, affect the growth of my bamboo? Will it easily recover, or am I looking at drastically stunted growth?