More importantly, what varieties are CLUMPING and winter hardy (zone 5)?

I also have a hard time finding any clump-type bamboo that can surrive
in colder climate (northern half of zone-6). The clump-type bamboo
that I tried two years ago was supposed to have "some" chance of
surriving in zone-6. But they all died after one winter.

The only bamboo that can surrive in my backyard are a type of "runner"
bamboo that spread very fast in spring. I didn't plant them. They are
from my neighbors (I don't know which neighbor because they come from
the backyard of two of the nearby neighbors). I don't mind them even
though they are runner. they look good and they provide a privacy
screen to my backyard. If they spread to my lawn, I can easily mow
them down.

Jay Chan