There are other bamboos that look like Al Karr but grow much larger, so you may have seen a different variety. Al Karr will only grow to about 25 feet here in Texas and with culms about 1 inch in diameter. Anything larger is a different kind of bamboo.

Al Karr will do very well in Houston and in full sun. Mine grows only to about 20 feet in height and after 12 years, has only spread to a width of about 5 feet and that's with extra water and fertilizer.

Kt

The picture of the plant at Mercer is at several sites, I have not seen the planting myself.

I'm going to go ahead and plant AK and hopefully it will behave as yours has.