Hello, fellow lover of all things green, It felt therapeutic to tend to the rejuvenation pruning of the Smokebush and other shrubs. Rejuvenation pruning involves drastically cutting back overgrown plants to restore them to their intended shape or to manage their size, which was the case of my Smokebush (aka Smoke Tree) rising above the roof.
About Smokebush (Cotinus coggygria)
Garden Design by Mary Stone, Stone Associates Landscape Design & Consulting
‘Royal Purple’ Smokebush (Cotinus coggygria)
Cotinus coggygria is a fast-growing shrub that bursts into bloom in summer and resembles puffs of smoke, hence the name. It grows ten to fifteen feet tall and wide in Zones 5 to 8 and prefers full sun. It can tolerate a range of soil pH but prefers slightly acidic soil. But it fails in soggy soil, so good drainage is essential. Once established, it can tolerate drought.
I should mention that according to the North Carolina State Extension Office, the plant has low-severity poison characteristics. For some, contact with the plant sap may cause contact dermatitis. So protect yourself with long sleeves and gloves if you are allergic.
Mine is a ‘Royal Purple’ Smokebush—one of the dark purple varieties. It lives in part-sun, so it doesn’t purple up as much as it could. The leaves are greenish-purple, but it’s still a lovely plant that turns reddish-purple in the fall. It’s a standard, meaning trained to have a single trunk.
How to Rejuvenate Prune Smokebush
To rejuvenate Smokebush, randomly cut the branches to just above the next growth node (where new stems grow) to lessen the canopy by about one-third. Cleanly cut at a slight angle about a quarter inch from the branch collar to remove an entire limb. Make clean angular cuts to prevent insects or disease, being careful around the trunks of these beauties as their wood is tender.
You can also rejuvenate clump Smokebush to control its size. Cut it to six to eight inches above the ground, much like we do Butterfly Bush (Buddleia davidii). Of course, don’t prune a standard Smokebush close to the ground, as it will revert to its clumping natural shape.
The best time to rejuvenate prune is before budding begins in late winter or early spring. Young Smokebush can shoot up odd branches – growing tall before filling out. I suggest pruning the unusual shoots as they come along to encourage thicker branching.
Other shrubs to rejuvenate prune in spring
Other plants I rejuvenate pruned, cutting it to half its size, are the Little Princess Japanese Spiraea (Spirea japonica) and Cinquefoil (Potentilla fruticosa). Like Butterfly Bush, they bloom on new wood so we won’t miss out on the flower this season. Smokebush, on the other hand, flowers on old wood. Therefore, it will be a few seasons before the revitalized plant returns to its puffy glory of blooms.
Newly installed Smokebush may also take a few years to bloom. But there are miracles in new beginnings, just as in our lives. As we go through difficult times, please take comfort in knowing we can revitalize and restore ourselves. Have faith that the new beginnings occur after endings. It brings us hope.
Garden Dilemmas? AskMaryStone@gmail.com (and now on your favorite Podcast App.)
There’s more to the story in the Garden Dilemmas Podcast (10 soothing minutes):
General Pruning rules of thumb:
Early spring is an ideal time to prune evergreen shrubs like juniper and yews and deciduous shrubs not known for flowering, such as Red Twig Dogwood and Ninebark. Otherwise, the rule of thumb is to prune after shrubs flower. Boxwoods can be pruned anytime through summer (no meatball shapes, please).
It is of utmost importance not to prune plants late in summer or early fall, as this may encourage new growth that will not have time to harden off, causing winter damage. Also, late pruning stresses plants, as they put energy into their roots rather than new growth that time of year.
A previous related column you’ll enjoy: Spring Cleanup & Pruning Lavender
To learn about more varieties of Smokebush, click through to the National Gardening Association’s Cotinus Selections.
I have two Smokebushes in my yard and only recently figured out that these were the source of many bouts of excruciating dermititis. It seems these are in the se family as poison ivy, and anyone who is sensitive to poison ivy is likely to endure several weeks of hell after pruning their smokebush, unless they take extreme caution to not actually touch the bush they are pruning. I am surprised that online advice about these plants (such as yours) doesn’t make this hazard very very clear.
Hello Todd, Oh my! I had never heard of anyone having such a dramatic reaction to smokebush. I am highly allergic to poison ivy and just finished having an episode all over my arms. I think my new rescue transferred the oil onto me while removing a dozen ticks (ick). Now I scrub with Dawn dish detergent afterward.
Cotinus coggygria is poisonous if ingested as many plants area. And, they may cause skin irritation, much like leatherleaf viburnum (V. rhytidophyllum), which causes an itchy, thankfully temporary, rash all over my arms when I prune them. Yours is the first I’ve heard about smokebush causing such a terrible reaction. Thanks for sharing your warning. Take CARE! Mary
Can a mock orange bush be pruned in spring before flowering? Thanks
Hi Naida, Mock Orang blooms on old wood (the previous year’s growth), so you will miss out on the bloom. It is best to prune right after they finish flowering in early summer. If you’re doing a drastic pruning, they may not flower next season as they rejuvenate. Thanks for reading the post! Mary
I have no mowable groundcover in my yard, so my smokebush is making far too many seedlings. If I’m willing to sacrifice blooms, will I prevent seedlings simply by doing a rejuvenation pruning each Spring? Or are the seeds and seedlings not all coming directly from fallen blooms?
Hello there, Smoke bush blooms on old wood so your idea of rejuvenation pruning each Spring is perfect. Thank you for reading my post, Mary
Okay, great! Thanks for your reply!
Please enlighten me about the boxwoods and meatball shapes. Thanks!
Hi Barb, By meatball shapes, I mean pruning boxwood into balls. I prefer plants to grow in their natural shape. But some folks like balls, I suppose. Use sterilized tools when pruning, as boxwood diseases are spreading rapidly. Thank you for reading my column post, Mary Stone
Hi Mary – I have a smoke bush that we had to transplant last fall due to putting an addition on our home. This spring, it only bloomed on the left side. The tallest section in the middle and the right side did not bloom. They are just branches. Do you have any insight as to whether I should cut those branches off or if there is a possibility it may bloom on those branches next season?
Hi Kat, As long as there is foliage on the branches, I’d leave them. The plant settles in after being moved and puts energy into restoring roots rather than blooming. If there are any dead branches, go ahead and prune those. The fact that it bloomed at all is impressive. A successful move! :^) Thank you for reading my post, Mary Stone
Hi Mary – I am puzzled as what to do with my Smoke Tree. It is mid-August and all the information I’m finding is to prune in the Spring. After 5 years of replanting in clay soil I’m finally realizing it does not need much water. However the damage is done. This year it grew very long branches with smoke puffs and leaves at the end of a branch with no foliage on the rest of the branch. The smoke puffs with the leaves are presently dying. There is still some foliage on the rest of the tree that looks OK. I need to prune the dying puffs to keep the tree looking nice before it goes dormant. Is this OK to lightly prune it? or will this mess up it’s growth cycle? Thank you for your help!
Hi Julie, I’d go ahead and prune it. There’s still plenty of time for the stems to harden off before winter. If it needs a more ambitious haircut in the early Spring, it’s an excellent time to rejuvenate prune. Thank you for reading my post! Mary Stone
Hi Mary_ My smoke tree is very leggy! It’s about 10 years old and in the sun. Its color is so pretty but the leggy look is not what I like. It’s shading my peony and I’m not happy about that. It needs pruning, and I guess it’s too late now. I want it to be fuller throughout the branches. I don’t quite understand your pruning method. Maybe another explanation will help me. Thanks….Judi
Hi Judi, From what you describe, I would consider rejuvenating the plant by cutting it to six to eight inches above the ground, much like we do Butterfly Bush (Buddleia davidii) – down to sticks. Of course, don’t prune a standard Smokebush close to the ground, as it will revert to its clumping natural shape. If your plant has a single trunk, rejuvenate it 6 to 8 inches from where the canopy begins.
Or, you can cut it down to whatever height you’d like to start to thicken up branching – each truck of the clump and random heights. Smoke Bush rebounds quickly. You’ll miss out on blooms in the first season. Going forward, prune branches yearly to thicken them further to your liking. The best time to rejuvenate prune is before budding starts in late winter or early spring.
I hope this helps. Thank you for reading my post! Mary Stone