I chopped the top off my large plant. I then took a knife and cut into the stem of the cutting at 45 degree angles. This allows the plant to suck in more water with more exposed flesh to gather the water.
Now, I know that you are supposed to wrap the cutting in a growth hormone powder, but I didn't have any, so I've just put it in the dirt and used a natural fertilizer. It also needs to be in a warm humid environment, so I will keep my water bottle handy and mist the leaves whenever I think about it. Some people put a plastic bag with air holes around it. I want to see what happens without. Thus, my little umbrella plant should start growing roots in about 2-3 weeks! I will then transplant it back into the original pot and have a nice little bush growing. Cross your fingers and I'll keep you updated on the success of my Schefflera aboricola.(note: I've also heard that you can do the same thing with the leaves, so I plucked a couple of those, and threw them in the dirt after a similar process as larger stem. You can also put it in water, theoretically. I've never attempted it before, but I hear that this method also propagates roots.)
