Q: I have a really tall corn plant. It nearly touches my ceiling. Can I divide it somehow to save it and to make a new plant?
A: You can’t divide the corn plant unless it has a new stem that has come from the soil near the original plant. If that’s not the case, you can make a new plant by “air-layering” the mother plant.
(By the way, this works for many other plants: hydrangea, camellia, azalea, etc)
Choose a spot 12 -24 inches from the top of the plant and gently scrape away the bark in a half-inch wide band around the stem. Dust the wound with a rooting hormone like Rootone. Get some long fibered sphagnum moss (not peat moss) and soak it with water. Squeeze it until it is damp, then wrap it around the wound. Wrap thin kitchen plastic around the moss and tie it in place with masking tape. Wrap everything with a sheet of aluminum foil. The plant will grow roots into the moist sphagnum moss, the plastic will keep things damp and the aluminum foil will exclude light.
Check it every month until you see roots inside the plastic. You can then cut the stem just below the root ball and plant it in a pot. The rooting will go faster if the plant is outdoors in a shady spot.