As the plant grows, the older leaves will yellow as new leaves appear. You can elect to do nothing and the yellow leaves will shrivel and be re-absorbed into the plant. If you do not like the appearance of yellow leaves, use a sharp knife to cut them off. I like to throw the cut leaves on top of the much to add even more mulch and return the nutrients back to the soil and plants. About a year after planting, your banana will form a flower .
Banana flowers can be huge.
They hang down pointing at the ground. The flower has flaps that will open upward in a series over many weeks. As each flap opens, you will see cup-like flowers. Pick one and drink the liquid . You won't believe how wonder the nectar tastes.