How to Prune Smoke Bush
There are two options when it comes to cutting back this colorful shrub
Smoke bush (Cotinus spp. and cvs., Zones 4–9) has amazing foliage that comes in an array of colors and beautiful, plumelike blooms. Which trait you care more about will determine how you prune this shrub.
Steve Aitken, a former editor at Fine Gardening, and Joann Vieira of Tower Hill Botanic Garden show how to prune Cotinus, more commonly known as smoke bush.
If you’re more interested in keeping your smoke bush shorter so you can appreciate its colorful foliage close up, then you should cut the stems back in winter. You can leave just 6 to 8 inches of the stubby branches emerging from the ground. This is classified as hard pruning or renovation pruning and can be done every year if you wish. Be careful about the sap that can emerge from newly cut stems. For some folks that sap can cause a minor skin irritation. Also, be sure to wash that sap off your pruners after using them so it doesn’t cause corrosion.
TIP: Pay attention to the buds to direct new growth
The small black nubs along the stems of smoke bush are the buds for next year’s growth. If you selectively prune back to just above a bud that is facing outward, the new growth will shoot outward from the shrub. If you cut back to just above a bud that is facing inward, the opposite will happen.
If you want to enjoy the fun smoke-ish flower plumes the next year, cut the shrub back by only half. This will ensure that the old stems provide ample flowers for your enjoyment. The technique is considered rejuvenation pruning or light pruning and can also be done every year. Eventually your shrub may become too tall or gangly for your liking, and you may want to sacrifice the flowers one year to get the shrub back in shape.