cut a stem with a razor.. place in a glass of water.. within the week it will root..

plant that and be done with it ..

i am not aware of one being able to divide them ..

ken

Right, technically you can't divide something that only has 1 stem. But I do this every year, just before the first frost. I cut off every decent stem and put in water, place in bright windowsill, replant in spring. Remove all leaves that would be submerged.

A few Coleus (and other) cuttings saved and replanted this spring, about 8 plants.