Black bamboo is hardy to zone 7, but that refers to plants in the ground. Container soil can get colder than the ground it sits on. What are the planters made of? Concrete and clay provide the best insulation against cold. After that it's wood, and polyurethane foam, then thin-walled fiberglass and plastic or metal planters. Make sure the plants are well watered before cold weather and during the winter if rain is scarce. The fence provides protection from cold, drying wind which often is more damaging than snow or ice.

Ok here is what I found about the planters. They are not concrete or clay. Do you think this is sufficient or I heard I could wrap planters with bubble wrap - not too true this is

Yes, polystyrene foam is good too. I like the foam planters because 1) they are lightweight and 2) they provide some insulation from cold, kind of like an ice chest in reverse.

I've never used bubble wrap, but I have read about people using it inside the container. They line the walls of their planter with the bubble wrap and then add the potting soil. Since you have already planted your containers, you would need to wrap the outside. Bubble wrap is a cheap fix that would give you more piece of mind.

I've seen the tops of long established black bamboo growing in the ground hammered by a winter here in USDA 8 where it got into single digits F. even in some locations near salt water. So if you ever see forecasts for maybe, say, 15F or even 20F there you should probably think about dragging your planters into an intermediate location like a garage. Or covering them with something that will provide significant protection.

One cold tolerance study involving a variety of different woody ornamentals found a shared tendency for specimens in containers to be about 20 degrees F. less hardy than the same kinds established in the ground.

Bambooweb says black bamboo is hardy to -15C. Which equates to 5F. They are of course talking about established plants in the ground.

http://www.bambooweb.info/BrowseSSL.php?Units=M&Sort=Gs&Genus=Phyllostachys&DiaValue=+&HtValue=+&TempCompare=%3C%3D&TempValue=+&SunValue=+&Clumper=NULL&Match=AND&Button=GO

Hi Perretak- where did you get your black bamboos and horsetail from? I’m in Atlanta too but couldn’t find any nursery that sells bamboos/horsetails. Love your planters! I’ve been thinking about doing something similar to divide our outdoor dining and lounge area.