About half to a third of the winters around here kill off most or all of the above ground parts of my grove.

I suppose a well developed root system would minimize culm frost damage. So is it too late to transplant (into the ground) Phyllostachys Nigra in late August? Some of the culms I'd like to move are 15 ft high, some of which I've had in pots, under a shady tree, for 2 months. Thanks, regards, Hansel de Sousa