Bambusa are tropical and do not usually persist outdoors here. Typical minimum temperatures given for the hardiest Bambusas are teens and twenties Farenheit. And that's a short duration exposure in a southern climate where the soil does not become chilled and the weather will warm up again right after the cold snap. (You must be in Port Townsend if you think you are in USDA 9).

Bring it back by watering it consistently. Do not leave it outside during cold periods, such as the one we just had.

...the stems of this one come up close together. You would only need a barrier if you did not want the clump to become broad after many years. It will never take off and pop up several feet or yards away.