The common houseplant known as lucky bamboo is actually a lily, from the family dracaena, in disguise. If one of your lucky bamboo stalks is getting too tall, you can slice off the extra length just below one of the obvious joints. This is also the best way to propagate lucky bamboo. Given the appropriate conditions, your bamboo cutting will quickly sprout roots and can be added back into the parent arrangement or used to start a new arrangement of its own.
Rooting the Cutting
Place the bamboo cutting in a small, shallow bowl filled with 2 inches of spring water.
Pour small pebbles or beads into the water around the base of the bamboo stalk until they stabilize it so that it can stand upright.
Place the container in a warm, bright room, but keep it out of direct sunlight.
Check the water level in the container every two or three days. Replenish as necessary to keep the water at the constant 2-inch level. Change the water entirely every week, taking care to disturb the plant's developing roots as little as possible. The cutting is ready for transplant to a permanent home once you can see substantial root growth up to the water level.
Maintaining the Cutting
Keep your cutting in the container it rooted in and add other bamboo stalks to create a pleasing arrangement or, if you prefer, transfer it back to the parent arrangement. Just place the stalk, roots, pebbles and all, in its new home, cover with water up to the level of the roots, and leave it be.
Keep your stalks or cuttings, once rooted, in a brightly lit room, out of direct sunlight. You can move them to other lighting conditions gradually, giving them time to adapt, if necessary. Bamboo will adapt to almost any lighting condition except direct sunlight, which burns its leaves; it can even survive in the total absence of natural light if illuminated by indoor fluorescents.
Continue changing your cutting's water once weekly as the plant matures. This is standard care for lucky bamboo. As during the rooting stage fertilizing is not necessary, but you can add liquid fertilizer, diluted to 10 percent strength, every time you change the water if you so desire.
Keep a constant eye on the water level in your bamboo plant's container; keeping this at the same level by topping it off every day or two with fresh water is the most critical element of bamboo care.