Gerry, a customer from Islamorada, FL wrote to say:
The hedge bamboo we bought from you is doing great.  There are lots of new shoots coming out of the ground and it’s getting tall with a lot of full growth on the upper third of the stem. Is it OK to “top off” the tallest ones in order to encourage new leaves near the bottom, or should we wait for it to fill in on its own?

My response:
I would suggest waiting a little while longer, Gerry.  New bamboo shoot grow tall quickly then take their time leafing out beginning at the top and working their way down to the bottom.  Keep in mind that the above-ground growing season continues until November so you can expect many, many more new shoots to emerge before then.  Your clumps will be full and leafy by the end of the year.  At that point, if there are any canes that are bare at the bottom but leafy at the top, you can top them to encourage new lower leaf growth.  Keep in mind though that once a bamboo cane is topped, that cane will never grow any taller. 

New shoots begin to leaf out from the top and work their way down toward the bottom, a process that takes several months to complete.