Here is a link to an article on the care of mums. At the bottom is some info on propagation.

Mums are usually very easy to propagate. It doesn't matter which stem you cut off, but you generally want one which is actively growing and is green and soft (this holds true for most anything). On mums this usually means any stem.

You can also divide mums their second year by simply cutting the plant in half, leaving roots on each half.

Yes, it's true! Stuff a stem in the ground and keep watered and you will get a new plant. I have started hundreds in my yard that way. I keep them trimmed down in the spring so they bloom in the fall and it's the spring trimmings that I use to start new plants (but you can do it at any time with mums).

I used them to fill in my beds until my other perennials grew up. I have some started that way that after a couple years, almost qualify as bushes because they are so big. I have removed a lot of them since but the ones that are left the my main fall color in the beds.

The nicest thing about garden mums is that you can trim, cut, divide, or move them almost any time of year and they just keep thriving!

Thanks for all the great info. !!! Can't wait to start planting!