How should I manage my cold-damaged black bamboo clums?

[hdesousa]

My black bamboo grove is around 10 years old. I had 100% die-back in the first few winters, but recent winters have been kinder. Last Spring my largest clums were just under 30mm diameter.
But this past winter was brutal (Zone 5/6), Lehigh Valley, Eastern PA, USA.
Most clums appear completely dead, and the rest have new leaves sprouting from branches that are 1- 1 1/2 m from the ground. Should I cut all the old growth down to the ground?
(see attached pics)
Is there any benefit to only cutting a clum down to where there are some new leaves appearing?
(Unfortunately, the new clums are now under 20 mm diameter.)
thanks,
Hansel

[stevelau1911]

It looks like they got set back a year from a top kill, but I would get rid of everything top killed completely, or appears to be struggling to put out leaves since they only take away energy that would be going to new shoots.

My vivax about the same cold hardiness as p nigra was completely topkilled from a harsh winter and it was the only plant in my garden to downsize despite being known for the fastest to upsize. I cut down the dead culms once I saw new shoots and realized they weren't going to leaf out, or might waste energy trying to.

[ghmerrill]

I always look at every leaf as an energy factory for the plant in total.... so if something looks to be leafing out, leave it, that means that the culm is alive, and can help to support the plant, via leaf structure, as well as energy storage for the plant. When you have massive die back like that, anything that is truely dead can be cut out, but I would say its too early in the year to start cutting back. I personally would wait a few more months, maybe cut out the dead stuff this fall. I is always easier to take something out later thant to wait for it to regrow.....