Linda try laying the long stem on a shallow tray of soil, leaving it attached to the main plant. About two inches from the crested growth put soil over the stem (on the parent plant side of the crest. Place a rock over the dirt, without the rock touching the crested part. That way you can let it continue growing through the winter without worrying about whether it will root or not this time of year.
Or you can cut it off about 2 inches below the crested part and put it into a pot of soil, burying the stem almost up to the crested part.