I have been told by "experts" that is very difficult to propagate a smoke bush. In late April, I did some hard pruning in order to increase the amount of foliage on my smoke bush. I was told that by doing so, I would be sacrificing flowers & "smoke plumes". First off, I have not had this many flowers in the 8 years I have had this smoke bush. I would have to say that the pruning caused the bush to grow at least 3 times the flowers as usual. In other words, don't be afraid to prune!
My second point here; I have an array of Jack Frosts at the base of the bush, which cats seem to like digging and using as a toilet. The branches I pruned from the bush were inserted as a barrier around the Jack Frost plants. It kept the cats out, and as you can see from the picture, I now have what the wife calls, a "Baby Bush". I was told that a smoke bush cannot be propagated this way. I may have "planted" 10 or more of these prunings, but to get one to grow, is very fulfilling. From now on, do not throw away anything you prune from a smoke bush...you just never know.