My smokebush is a few years old, and has been doing well. It gets full sun, and is lovely, lots of fluffly blooms.
But this year, one side of it is dead! No leaves, no flowers. It tries to produce a few leaves, but they shrivel up and die.
The dead side is the one facing the sun. The other side looks perfectly healthy. Could it be getting too much sun?
Could it be bad pruning in the past? I did what I now know is called “non-selective pruning” at the desired height. I think I understand now how to do a better job, but could this have been the cause?
There was a chestnut tree in that spot a few years ago, and I still get some mushrooms coming up. Could there be some old roots interfering with my plant?
I’m at a loss. I don’t know what to do with the dead half, or how to prevent this from getting worse.
Thank you for contacting Toronto Master Gardeners with your question.
It seems your smoke bush suffers from over pruning.
Healthy smoke bushes (Cotinus coggygria) respond best to pruning in late winter/early spring, prior to leafing out. Dead branches, however, need to be removed regardless of the time of year. There are several Toronto Master Gardener entries describing pruning techniques for Cotinus. You could start with the following link below, and also search “cotinus” on the Toronto Master Gardeners website. This link also refers you to an instructional video which may be of use. https://www.torontomastergardeners.ca/askagardener/dead-limbs-on-smoke-bush/
You will note that there are 2 approaches to pruning. You can either prune back about a third of the branches to the trunk and shape the remaining branches, or, you can cut the shrub right back to within 5 to 7 cm of the ground (known as coppicing) to renew the entire plant. More information on coppicing is available from this (British) website: https://www.rhs.org.uk/advice/profile?PID=121
Recommend to prune out the dead sections right away, and leave the viable branches for this growing season.
Good luck with your smoke bush.