Pruning smoke trees
The smoke tree I planted 3 years ago needs fairly constant "pruning" because the branches grow rapidly, droop down to within 3-4 feet from the sidewalk, where passersby grab the branches and partially break them off. I try to follow good pruning practices when cutting off these damaged branches, but the structure of the tree is very unusual and makes it hard to determine how to repair the damage correctly. I looked online to see if there was advice about this and found info that smoke trees are actually bushes that are trained/pruned to look like a tree, but need to be pruned like a bush. Is this true? Suggestions?
Multnomah County Oregon
How to prune a Smoke Tree or Cotinus?
A Cotinus is indeed a shrub and not a tree, though most of the ones you'll see are trained to look like a tree with two or three branches acting as the 'trunk' and the foliage as the canopy.
You don't have to prune them like this, you can also prune them hard in Spring time and they will produce an abundance of fresh foliage and look more like a shrub. However if you choose this option you run the risk of missing out on the smoke-like flowers that Cotinus produces.
The question is really how do you want your Cotinus to look?
Oregon State University has not published any documents on how to prune a Cotinus specifically but I found this guide that shows you the two ways to prune your Smoke tree (shrub).
Thanks for your interesting question.