Smoketree

If you should ever find yourself luxuriating in the French Riviera, and in the unlikely event you grow tired of the sand and sea, a walk in the hills will introduce you to the unique woodlands of the Mediterranean.   There, among the scrubby oaks and umbrella pines you will find a familiar bush or small tree, the European smoketree – in its native environment.

There are only two species of trees in the genus Cotinus.  One is the American smoketree, the other is its close relative from Europe.  For both, their claim to fame is the wispy clumps of filaments that look all the world like smoke.  The mirage has given rise to other names such as mist tree, cloud tree, wig tree, and Jupiter’s beard.  By whatever name, the site of this tree is what Minnesota garden writer Don Engebretson has called “one of the most arresting shrubs available to…gardeners today.”

Another endearing trait of smoketree is its endurance under tough conditions.  Its native range from southern Europ through Turkey and Syria to central China has prepared it nicely for dry conditions and poor soil.  It is an easy tree to grow and it is well suited for urban situations. 

Smoketree can take many forms, depending on the space available and its use in the landscape.  With space to grow and no care, it becomes a full, handsome, multi-stemmed tree or shrub.  Or, it can be pruned to a small, single-trunk tree.  Or, you can ruthlessly cut it back to the ground each year and it will regularly pop up as a small bushy plant.  Whatever your preference, smoketree is a good candidate for adding to American landscapes.

 

 

Some Potent Uses for Smoketree

Smoketree and its relatives have powerful chemicals within their sap.  Traditionally, smoketree has been a source for clothing dye, and even today the leaves of smoketree are sometimes harvested in Europe for their tannin content.  Hemlocks and oaks are usually thought of as the big producers of tannin, but while their bark is around 10 percent tannin, this extract can be as high as 30 percent in smoketree leaves.

Interestingly, although the sap of smoketree sometimes causes an allergic reaction, the leaves are steam-distilled by some pharmaceutical companies and the resulting extract is sold for used in shampoos, toothpastes and as flavoring in the food, wine and tobacco industries.  There are also medicinal uses for crushed smoketree wood, but all of these uses should be left to professionals.

Despite its role both historically and currently, the best use of this little tree is undoubtedly ornamental.  Its striking appearance attracts notice and stands out from any other kind of tree or shrub. 

 

How to Plant Smoketrees

Smoketrees are less particular about site conditions than many species.  They have a fairly rapid growth rate when young or after severe pruning, but are otherwise classified as ‘moderate.’  Here is what to consider before planting this little tree.

  • Full sun or mostly sunny location
  • A wide range of soil pH is acceptable – from 5.1 (acidic) to 7.8 (mildly alkaline)
  • Ideal soil is well-drained loam; will tolerate other types, except wet soil
  • Tolerates low soil fertility and drought

 

Caring For Your Smoketree

Smoketree’s thin bark should be protected from ground fires, lawn mowers and weed cutters.  Water (but do not over-water) during dry spells when young, but after that it is not necessary.  In the spring, dead or diseased stems or branches should be pruned.  Otherwise, this species can do very well on its own with little or no care.

There are a couple of circumstances in which you may want to do more pruning.  One suggestion is to remove one stem in three about mid-spring to enhance flowering and foliage.  On the other hand, if for some reason you do not want the flowers (due to allergies, perhaps), smoketree can be pruned to ground level early each spring.  The new growth may reach six feet during spring and summer, with large leaves, better fall color, and no flowers.

WARNING: When pruning, wear old clothes because the sticky stem juice will cause stains.  Some people also have allergic reactions to this substance.

 

Smoketree: Cotinus coggyrgria

LEAVES:  Alternate on the branches and between 1 1/4 to 3 1/2 inches long.  Somewhat oval or egg-shaped with a smooth margin and distinct, parallel veins.  Petioles are 1/2 to 1 1/2 inches long.  Green to bluish-green in summer, highly variable in autumn but often bright orage or yellow.

FRUIT:  Clusters of small, dry, kidneyshaped furits about 1/16 inch in diameter

WILDLIFE VALUE:  Relatively low.

FLOWERS:  The actual flowers are inconspicuous.  They are about 1/3 inch in diameter with five yellowish petals, and sometimes containing both male and femal structures (perfect) and sometimes having one sex only (unisexual).  The flowers’ related structures are also complex and provide the showy feature of this species.  The clustered flowers are mounted on stalks (pedicels)  which in turn are borne on other stalks (peduncles) and all are on a 6- to 8-inch central stalk (panicle).  The finer stalks produce pinkish to cream-colored, hair-like structures that give the plant its smoky appearance from late spring through summer.

BARK:  Thin, reddish-brown with prominent, horizontal lenticels when young.

FORM:  A large shrub or small tree normally reaching about 15 feet in height with an oval crown spreading 12 feet.  Usually multi -stemmed with stout trunks. 

11 Comments

  1. I really like the shape and form of the common smoketree. This small tree fits so well into smaller urban landscapes, and can be planted in rows to form privacy screens or informal hedges. When it gets too big one can simply prune it back to fit the site.

    I sure would like to see the Foundation begin to offer the American smoketree, Cotinus obovatus.

    At an arboretum I saw a dark purple leafed cultivar of the common variety planted beside an American smoketree and loved the beautiful contrast of the leaves. Fall color can vary on the American smoketree, but perhaps a plant breeder is already working on this? That said, I’ve see the American smoketree exhibit beautiful yellow, red, amber, and orange leaves in fall.

  2. are smoketrees sensitive to black walnut trees? I’M NOT HAVING any luck trying to grow a smoketree within the dripline of the walnut,number 2 is looking very sad. A pink one across the yard is thriving.number 1 is recovering in it’s new location. Proberly answered my own question.

  3. As an arborist I’ve never noticed smoketrees affected by the alleolochemicals produced by the roots of black walnut trees. Anyway, here is nice International Society of Arboriculture article explaining the wide range of trees & plants that produce alleolochemicals and their effect on other vegetation.

    I learned the roots of the smoketree tend to suppress the growth of grass which seems to make sense from what I’ve observed.

    Allelopathy and Arboriculture – THEORY TO APPLICATION – By Timothy Chick

    http://tinyurl.com/allelopathy

  4. Juglone is also highly concentrated in black walnut leaves, so its allelopathic effects may be seen outside a tree’s drip line as well. If you are concerned, watch for walnut leaf buildup and decomposition around your smoketrees (or anything else for that matter).

  5. Are smoke bushes sensitive to other plants growing near by?
    I want to plant flowers about 3 feet from the young smoke bush I have planted, move the flowers as it grows, but don’t know if they will cause it to grow in straight up instead of branching out into a bush. I am under the impression that you need to give the bush a clear growing area except for maybe a ground cover.

    Thanks for your comments

    • @Mary
      If your Smoketree is young you may want to wait on planting flowers around it. This is because the roots of the flower and tree will compete for some of the same nutrients.

  6. What are the effect of over watering the smoke tree? How does it react? My first year plants have brown spots on the leaves. Is this more likely to be caused by over watering or the many surrounding oak trees? It has been extremely hot and dry here in the mid-south this summer.