Do not divide this perennial. You can propagate Gaura from soft wood cuttings taken in late summer but this is a rather tender perennial so it is short lived in Western Washington as it hates our wet winters. Good for you on making it so happy! As for a haircut, you can cut back in the fall but not too much - less than one third as a severe pruning could stimulate growth and winter damage. In mid summer, once the plant has put on strong new growth you can cut back this perennial to eight inches tall and the flush of new growth will give you a second set of blooms. Enjoy the gorgeous gaura blooms and Keep Growing, Marianne Binetti P.S. Thanks for attending the talk this fall.