Question: I have a giant-leafed pothos whose leaves aren’t as big as they used to be. All the new leaves are much smaller. What has happened?
Answer: That’s almost the same answer as for the split leaf philodendron whose leaves aren’t splitting. When a pothos is allowed to grow up a support such as a tropical tree trunk, or a pole as a houseplant, its leaves get larger and larger. However, once they reach the top of the pole and start hanging downward, they revert to their smaller form. All the fertilizer in the world won’t make them grow any larger. All you can do is trim the stems back to the top of the old pole and enjoy the older leaves, or you can put a taller pole alongside it. Somehow, you’re going to have to keep the plant ascendant.