Is your black a clumper as in black lako? If so yes move it now! If it's a runner it should be, in your zone shooting, leave it alone for now. How deep depends on the root, the more the better for the plant. Deep to dig, as deep as it is now. Judge by the dirt mark on the cane. If it is a lako give it some afternoon shade, lots of water, and 6' of space!
Bud

Thanks for your reply. It is a clumper: Gigantochloa atroviolacea, also known as "Tropical Black". I'm worried about the timing to move it, because it put up its lone shoot in the summer last year. I don't know whether I'll do harm moving it just before it is ready to shoot or if I should wait until after??

On the other hand, I'm also worried about letting it stay in its same location where the Sunburst will be crowding it again as that bamboo puts up its MANY shoots...

What did you mean by "judge by the dirt mark on the cane", please? I guess I will just try and get as deep as I can.

Thanks again, I appreciate any advice.

You will see a dirt mark on the cane or canes from how deep it is now, try to keep it at the same depth!
If it is in fact a clumper move it now, as long as there are no new shoots above ground. Be easy in case it's buds are ready, but now would be the best time to move it!
Good luck!
Bud

Why, of course that's what you meant. Ha - sorry I didn't get it the first time - it's perfectly clear!

Thanks for the advice - I will try and figure out the mechanics of moving it now. And I have to figure out where to put it!

As I said just give it lots of room .
10' would be good and in a few years, boom BAMBOO in style!
Bud