Smoke trees, which are also called smokebushes, are popular houseplants that are known for their pretty leaves and airy flower clusters. Smoke trees need to be pruned correctly to stay healthy and look their best. We’ll talk about when, why, and how to prune smoke trees in this complete guide.
Smoke trees belong to the genus Cotinus and are native to wooded areas of North America, Europe, and Asia. There are several species, including the American smoke tree (Cotinus obovatus) and the more common European smoke tree (Cotinus coggygria).
The tiny flowers on smoke trees grow in big, puffy clusters that look like puffs of smoke. This is how the trees got their common name. The flowers start out green, but as they grow, they turn into pink or gray plumes.
The leaves of smoke trees also provide visual interest. Depending on the variety, they may be green, purple, pink, yellow, or various shades of red and orange. The foliage often changes color through the seasons, providing a show of color.
Smoke trees thrive in full sun and well-draining soil. They can grow 15-20 feet tall and wide when left unpruned, taking on a rounded shape. Alternatively, with pruning they can be maintained at shrub size. Read on to learn how to prune smoke trees to control their size and shape.
When to Prune Smoke Trees
It is very important to prune smoke trees at the right time of year to keep them healthy and in good shape.
The best time for major structural pruning is late winter or early spring before new growth emerges Pruning in late winter or early spring avoids removing flower buds and gives the smoke tree time to recover before the demands of the growing season
Anytime of the year is a good time to do some minor maintenance pruning to get rid of dead or damaged branches. But don’t prune the smoke tree too much in the spring and summer, when it’s growing quickly.
Here are the key things to know about timing your smoke tree pruning:
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Late winter or early spring before buds open is best for rejuvenation or structural pruning. This avoids removing flower buds.
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Summer pruning should be avoided other than removing dead or damaged branches as needed. Pruning in summer can stress the tree.
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Fall pruning is not advised as it may stimulate tender new growth before winter dormancy.
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Throughout the year small prunings to remove dead, diseased, or damaged branches can be done as needed.
Why Prune Smoke Trees
Pruning is beneficial for smoke trees for the following reasons:
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It maintains a desirable shape and prevents leggy, uncontrolled growth.
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Opening up the interior allows more airflow and light penetration.
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Removing dead and damaged branches improves health.
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Pruning rejuvenates and revitalizes older trees.
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For multi-stemmed smoke trees, it maintains an even distribution of branches.
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Pruning controls size and enhances flowering and foliage effects.
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On young trees, it helps establish a strong structure by removing problematic branches.
How to Prune Smoke Trees
Smoke trees are flexible when it comes to pruning. You can lightly trim each year to maintain shape, or do periodic heavy pruning to rejuvenate old specimens. Here are some key smoke tree pruning techniques:
For light annual pruning:
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Remove dead, dying, and damaged branches anytime they are spotted. Prune back to healthy wood.
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Select and remove branches that are rubbing together, cracked, or growing erratically.
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Shorten or remove branches that spoil the desired symmetrical shape.
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Selectively thin inner branches to open up interior to light and air. Remove up to 1/3 of old branches.
For rejuvenation pruning:
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Cut main branches back to just above the trunk to force new growth. Can be done over several years.
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On older neglected trees, cut all branches back to within a few feet of the ground in late winter. This will yield a smaller but revitalized tree.
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Remove old, thick branches all the way to their origin to encourage new replacement shoots.
For training a smoke tree as a tree:
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Select one main upright stem to be the leader and remove competing stems.
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As the leader grows, prune off lower side branches to elevate the canopy.
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Maintain one dominant leader by pruning off competing shoots.
Helpful Pruning Tips
Follow these tips for safe and effective smoke tree pruning:
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Always use clean, sharp pruning tools to ensure precise cuts and avoid injuring the tree.
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Prune just outside the branch collar, the raised area where a branch joins a larger branch or trunk.
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Use proper cutting techniques, cutting at an angle just above an outward facing healthy bud.
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For large branches, use the three-cut method to prevent ripping of the bark.
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Clean pruning tools with rubbing alcohol after each cut to disinfect.
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Apply pruning sealer to cuts over 1 inch in diameter.
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Remove sap or debris from tools during pruning to prevent spreading disease.
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Never top trees or remove the central leader. This can lead to weak growth.
Maintaining Smoke Trees Post-Pruning
After significantly pruning smoke trees, provide a little extra care to help them recover:
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Water thoroughly after heavy pruning to reduce stress. Continue with deep watering while new shoots develop.
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Stake branches that were heavily cut back to prevent breaking until regrowth is stronger.
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Apply a balanced fertilizer or compost around the root zone to fuel regrowth.
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Monitor for pests like borers that may attack stressed or wounded trees.
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To prevent sunscald, paint any exposed bark with white latex paint diluted with water.
With proper annual pruning and occasional rejuvenation pruning, smoke trees can thrive for decades, providing stunning spring flowers and beautiful foliage. Follow these smoke tree pruning guidelines for the healthiest and most gorgeous specimens in your landscape.
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