Cotinus
( KOE - tye - nus )
At-A-Glance Information
Cotinus (commonly called Smoke Tree or Smoke Bush) is a genus of deciduous shrubs and trees that needs full sun and moderate water. These are unusual looking plants, that form colorful, 'smoke-like' mounds that are usually as wide as they are tall. Naturally multi-stemmed, most plants can be trained into small trees, and are perfect for border plantings, as specimens in containers on patios, as hedge shrubs, or to soften building walls. Take care when planting Smoke Tree in your garden, as they are related to Sumac and their sap can be toxic to humans.
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cotinus Species and Varietals
The genus Cotinus includes seven species, and is closely related to Sumac. They are included in the family Anacardiaceae. The common name Smoke Tree comes from the fact that the flower heads have a fluffy look to them, and mimic smoke from a distance. Cotinus grows best in zones 2-24. For more growing information, see the species descriptions below. To find your zone, click here: Zone Map.
Cotinus coggygria
This shrub is native to southern Europe and China, and is commonly 12-15 feet tall and just as wide, though older plants can reach as much as 25 feet tall. Leaves are bluish-green or purple. Varieties with purple foliage will have more intense color when planted in full sun. Commonly grown varieties are listed below.
Caring for and pruning cotinus shrubs
Plant Cotinus in full sun exposure (at least 6-8 hours per day of direct sun) in spring or fall, and build up soil about three inches tall around the bottom of the canopy to create a watering bowl. Smoke Trees are relatively drought-tolerant but will benefit from a deep watering every two weeks during the warmer months of the year. This bowl will help with the process. Fill the bowl with mulch, taking care not to let it get too close to the trunk. These shrubs can grow in a wide range of soil types and textures (including sand and clay, though they grow best in well-draining loam), and prefer soil pH to be kept between 3.7 and 6.8. Smoke Tree enjoys moderately fertile soil and will benefit from a yearly springtime feeding with an 18-6-12 fertilizer applied at the base and watered in.
How you prune your Smoke Tree is dependent on whether you are keeping the plant as a shrub or creating a tree. If you are shaping into a tree, choose a main trunk and cut back all others in late winter before new spring growth occurs. Once your tree has been formed, only prune in early spring to remove dead or damaged branches. If you are keeping your Smoke Tree as a shrub, cut it down to a few inches tall in late wintertime in the first two years to promote fuller growth and stronger main stems. Once your desired shape has been achieved, prune yearly in early spring simply to remove dead or damaged branches. Smoke Trees also do well when planted in containers. These plants will require more water and care than those planted in the ground; provide weekly waterings and do not allow soil to fully dry out in between. Every two years, take it out of the pot, clean up roots, provide new soil and repot (if necessary, in a larger container).
How you prune your Smoke Tree is dependent on whether you are keeping the plant as a shrub or creating a tree. If you are shaping into a tree, choose a main trunk and cut back all others in late winter before new spring growth occurs. Once your tree has been formed, only prune in early spring to remove dead or damaged branches. If you are keeping your Smoke Tree as a shrub, cut it down to a few inches tall in late wintertime in the first two years to promote fuller growth and stronger main stems. Once your desired shape has been achieved, prune yearly in early spring simply to remove dead or damaged branches. Smoke Trees also do well when planted in containers. These plants will require more water and care than those planted in the ground; provide weekly waterings and do not allow soil to fully dry out in between. Every two years, take it out of the pot, clean up roots, provide new soil and repot (if necessary, in a larger container).
Propagation
Cotinus can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Smoke Tree, follow the instructions below:
Propagating Cotinus by Cutting
Propagating Cotinus by Seed
Propagating Cotinus by Cutting
- Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, a plastic bag, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
- In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more semi-ripe 6-8 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much. Place a plastic bag over the pot and secure it around the rim of the pot.
- Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth on your propagated shrub, you'll know you have roots. You can remove the plastic bag at this time, but keep the cutting growing in a protected, warm location.
- Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.
Propagating Cotinus by Seed
- Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a bowl filled with lukewarm water, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
- Harvest your seeds in September or October. The seed pods on Cotinus plants are pretty easy to spot, they're left behind after the smoke puffs have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
- Fill your bowl with lukewarm water, and soak the seeds for 12 hours. Then, carefully take the seeds out, replace the water, and let them soak for another 12 hours. Drain the bowl and let the seeds dry out completely. Then, place your seeds about in your prepared seed tray or pot about 3/4 inch down into the soil. Cover with a dusting of more soil and water, taking care to not wash away the small seeds.
- Germination can take up to two years from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
- Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Problems and Pests
Cotinus is rarely bothered by pests or disease.
Gallery
Videos
A video about some of the best species of Smokebush.
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How to care for Smoke Tree.
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All about Cotinus (Smoke Tree)
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A how-to video on pruning Cotinus shrubs and trees.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 267, Cotinus
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