This is a question I get fairly often: "Can I trim my lucky bamboo?" You'll note that my friend below is getting a little on the hairy side ...
Healthy lucky bamboo grows fairly quickly and will grow out of whatever neat shape it started as. Worse yet, the stalks tend to grow straight up and the plant quickly becomes leggy and top heavy. And who wants a top-heavy vase full of water on a desk near electronics?
Yes, you can trim lucky bamboo, even sort of aggressively. Cut tall stalks back down to the original stem, and they will regrow. You can then use the trimmed stalks to root new plants. Alternatively, reshape the plant by selectively trimming the taller branches. It will lose its compact shape, but it will be an attractive plant nonetheless.
Photo © Jon VanZile