Smoke trees, also known as smokebushes, are a popular ornamental plant known for their airy plumes of flowers and attractive foliage. Proper pruning is key to keeping smoke trees healthy and looking their best. In this comprehensive guide, we’ll walk through when, why, and how to prune smoke trees.
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).
Smoke trees get their common name from their tiny flowers that bloom in spring or summer in large, puffy clusters that resemble puffs of smoke. The flowers emerge green but mature to pinkish or grayish 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
Pruning smoke trees at the right time of year is crucial to maintaining their health and form
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
Minor maintenance pruning to remove dead or damaged branches can be done anytime throughout the year. But refrain from heavy pruning during spring and summer, when the smoke tree is actively growing.
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.
When to Prune Smoke Tree
Smoke Trees are low maintenance and do not require pruning regularly unless you are trying to ultimately change the nature of the plant. If pruning is necessary, do so in the early spring when the plant is still dormant, before it begins producing flower buds. Keep in mind that pruning a Smoke Tree before it blooms may reduce the amount of flowers it can produce. Once bud sites have been set, pruning is not recommended.
Maintenance pruning can help keep your Smoke Tree looking healthy. Remove any dead or damaged branches as they occur. To improve airflow, remove any branches that cross into the center of the plant, in the spring. If your Smoke Tree has grown too large and you are looking to start fresh, you can cut its branches back to the ground in the winter. This will allow the plant to produce completely new branches. Your Smoke Tree will not produce blooms the following months after such a drastic prune.
Why Prune Smoke Tree
Smoke Trees require little fertilizer, pruning, and care to grow. Being low-maintenance plants, Smoke Trees can go their entire life without needing to be pruned. This is one of the benefits of choosing the right-sized plant for the right space. Smoke Trees can become unruly, however, which is why some gardeners choose to prune them regularly. Pruning can also improve air circulation, reducing the risk of foliar issues. Hard pruning Smoke Trees to the ground, called renovation pruning, can keep Smoke Trees more compact, but your plant will be focusing on producing new foliage rather than blooms.
Why You Should Prune Smokebush and How to Prune It
FAQ
When should I prune my smoke tree?
Only prune in early spring before the plant leafs out. Crossing, badly formed or damaged branches should be removed back to a main branch. Dead branches are the challenge in keeping a nice form.
How do you take care of a smoke tree plant?
A tough plant, Cotinus Coggygria performs best in full sun, in average, medium, well-drained soils. Purple-leaved varieties planted in shade may see their leaves turn green. Smoketree is not fussy about soils provided they are not soggy or wet. Good drainage is essential.
How long does a smoke tree last?
Although the smoke tree is short lived with a lifespan of about 20 years, it requires little maintenance. The Fall color is highly variable, but at its best produces very attractive shades of yellow, orange, red and purplish-red.
Can you keep a smokebush small?
In late winter or early spring, cut out dead, diseased and crossing branches, and lightly shape as needed. Since smoke bush blooms on the previous year’s growth, hold off on any major pruning until after summer flowering. Plants can also be kept smaller by cutting them back hard to the ground.