poaky-
I grow it in Zone 8 and it's highly controllable. In your Zone, I think it will be at leasst several years before it does anything much to be of concern. I don't use barrier with mine. I just chop wayward rhizomes once a year.

Thanks Kudzu, I am hoping that I can get some soil to make a mound with to make it easier to trim up rhizomes in the future.

I've planted several of my runners in mounds and it does help for rhizome discovery and pruning.

I received my Phylostachys Atrovaginata today. It is going to be 30 F tonight so it is in my unheated greenhouse. I am thinking of either getting some topsoil delivered to form a mound or building a HYPERTUFA container. I would build a framework of wood and chickenwire and coat with a cement sand and peat/ sawdust mix. I think rhizome barrier may be cheaper though. It will take years before I have to worry about rampant spread though.