Trimming your bamboo is essential to the overall health and maintenance of the plant. Each individual bamboo culm can live about 10 to 15 years, and proper pruning can ensure that your plant lives to its full potential. A full grove of bamboo can survive multiple decades, and each year, culms will require pruning due to death and decay. You should have a good set of sharp pruning shears and make your cuts just above a node in the culm.
Prune away any pieces of the bamboo plant that you see are yellowing, including leaves. Fallen leaves can be left at the foot of the plant for fertilizer in its soil, as bamboos prefer a more acidic condition. If you see the plant suddenly shedding all of its leaves prior to pruning, don't be alarmed. As long as you are giving it an adequate amount of water, fertilizer and light, this is probably due to the bamboo entering its dormant phase, which is normal before the time of new growth.
You will also want to clip away any new shoots the plant may produce. This will prevent the bamboo from spreading too widely, which is absolutely mandatory for a bamboo plant that is potted. If you notice new rhizomes emerging from the drainage holes at the bottom of your plant's pot, it is a good idea to shear them away. You may have to use a handsaw rather than your shears to do this, as these can become quite large and thick, even yam-shaped.
Be sure to also prune away any stalks you see on the bamboo plant that have turned yellow or that may have dried out. They should be cut at the surface of the soil and just beneath the lowest joint of the bamboo stalk. Be very careful when pruning this part of your plant, as you can accidentally damage other parts while trying to cut.
Another way to properly prune a bamboo is to cut the tops of it to ensure that it does not grow too tall. Depending on the thickness of your particular bamboo plant, you may need to use a handsaw, or you may be able to use your regular shears for this. After you cut the stalk, the bamboo will not grow any taller.
Another good practice you can use during or after the pruning of your bamboo plant is to separate your plants when they grow too large for their pots. It's a good idea to dig them up and out of the soil at their base and cut the smaller rhizomes away. These can be planted into completely new pots if desired, or you can throw them away. As a final alternative, you may want to consider using them for compost material. This can further nourish your bamboo plant.