Hi, I am a plant noob so please be kind. I have a lily plant that I have allowed the lily pads to grow to the surface to provide some shade for my discus. However, now all it does is shoot out lily pads at a an alarming rate and the bottom leaves are dying off. I would like it to start growing bottom leaves again and I will just get some floating plants instead for shade. Should I just keep cutting off the pads not allowing them to reach the surface, or will this just kill the plant?
Since the plant is healthy and growing quickly, just cut off all the leaves that have reached the surface, and any that look like they are headed that way. Usually, this causes the plant to slow its growth and produce only submerged leaves. This can last several months, then the plant will try for the surface again. You will quickly learn to spot a leaf that is going that way, and can cut it off before it gets there.
Lily Plant 
Linear Mode
