Lucky Bamboo Propagation
I have an extremely healthy Lucky Bamboo that has grown very large. It is a bonsai styled plant that I would like to leave the pattern of the base Bamboo. What I need to know is how can I trim its height and make the trimmings root for new plants without killing or damaging the existing plants.
You can just cut those stems off at any point you like to make your plant have a pleasing shape. You can then place those stems into some type of container with water, just like the original plant came in, with some stones for support; or you can plant them in moist rooting mix: https://www.gardeningknowhow.com/garden-how-to/projects/rooting-plant-cuttings.htm
If you want to keep your lucky bamboo for the long haul, however, you should consider putting it into soil. These are not water plants by nature; they're marketed that way because they are so strong and adaptable they will grow in water for a long time, but not forever. Here's more information: https://www.gardeningknowhow.com/houseplants/lucky-bamboo/growing-lucky-bamboo-indoor.htm