How much room does clumping bamboo need?

A customer recently wrote:

We purchased some bamboo from you last year. We have a quick question about
GIANT TIMBER BAMBOO (Bambusa oldhamii). How big can we expect the diameter of the clump to get. Just want to make sure we have it in a large enough area. The Blue, Black and the Asian Lemon bamboos are all doing well! Will send pictures soon!

My response:

Like all clumping bamboos, Giant Timber will always continue to send up new shoots around the outer edges of the existing plant. That means as the years go by, the circle of bamboo will get bigger and bigger. When you think it's large enough, vigilantly chop off or knock over the new shoots when they emerge in the late spring/summer. Once a new shoot is broken like that, it will stop growing.

If you're afraid the spot where you've placed the Giant Timber will fill up too fast, moving it would be a good idea. But, if you can, wait until December or January to do transplant. By then, all of this year's new shoots have completely grown up and leafed out. Moving a bamboo when it still has young canes often prevents the canes from continuing to develop and results in a loss of potential growth for those particular canes. Also, to make it easier to dig up the bamboo, the night before you plan to move it, thoroughly soak the ground around the bamboo. Wet ground is much easier to dig through.