Cotinus, the smoke tree that catches fire in fall

Silky plumes in shades from light pink to deep purple hover above oval leaves that turn from green or deep purple to yellow-orange as autumn nears. The smoke tree (Cotinus) earns its keep as a standalone, in a shrub bed or in a freestyle hedge. Give it full sun and well-drained soil and it asks for almost nothing more.

Cotinus at a glance

Name	Cotinus sp.
Family	Anacardiaceae
Type	tall shrub or short tree
Height	10 to 13 feet (3 to 4 m)
Breadth	6 to 10 feet (2 to 3 meters)
Exposure	full sun
Soil	any type, as long as well drained
Hardiness	-4°F/-20°C
Grows	fast
Leaves	deciduous
Flowering	summer

Excellent planted as a standalone, in a shrub bed and as a mixed hedge shrub.

Short presentation of Cotinus

Common: smoke tree, smokebush

The entire botanical genus for Cotinus stands out for more than one reason. Its leaves, first and foremost, have an unusual oval shape, and their color changes dramatically as seasons come and go, each species in its own way. You can thus choose between green and deep purple in spring, which then shifts to yellow-orange as fall comes near.

Flowers, secondly, are astounding: they’re clustered in bright silky plumes that are light pink to deep purple in color.

• In smoke bush (Cotinus), the smoky haze comes not from petals but from the elongated, plumose-hairy pedicels of the mostly sterile flowers, which is why the panicles look feathery rather than floral.
• Go easy on feeding: high-nitrogen fertiliser is well known to encourage soft, leafy growth, and gardeners commonly report that such lush growth delays or dulls the autumn colour of trees and shrubs.

Planting Cotinus

The smoke tree is satisfied with very little, as long as it gets sun and is planted in well-draining soil. This shrub is among the easier ones to grow, making perfect for beginner gardeners.

The rather large size it reaches hint at its preferred planting situation: directly in the ground in the garden. Nonetheless, since it also copes well with severe pruning, it’s also possible to plant it in a pot.

• It’s possible to plant Cotinus at the beginning of spring (late winter – early spring) or fall (early autumn to late autumn).

Cotinus in the ground:

• Dig a planting hole that’s more on the large and deep side.
• Enhance drainage in the soil with additional sand, or even gravel, to line the bottom of the hole.
• Remove the pot from the shrub, and pry a few roots out from the clump.
• Settle the shrub in the hole, and backfill, pressing the soil down firmly as you do so (watch out: don’t bury the root collar).
• Water abundantly the first time.

Cotinus in pots:

• Get your hands on a voluminous pot and check for presence of drainage holes.
• Along the bottom of the pot, add a layer of drainage, without plugging the drainage holes though. Possible drainage materials include clay pebbles, gravel or pebbles, and broken pot shards.
• Mix 2/3 soil mix with 1/3 sand and plant your Cotinus in this substrate, pressing the soil well against the clump.

Caring for Cotinus

During the first few years of growing, pay attention to watering, especially during droughts. When it has properly settled in, the shrub can cope with lack of water on its own.

Pruning:

It is not necessary to prune your smoke tree. However, you can go ahead and prune in order to maintain a denser, more balanced figure for your shrub.

You must prune at the end of winter. Smokebush blooms on new growth, so fresh shoots will be loaded with flowers in summer. Also remove dead branches and those that always get in your way.

If your Cotinus gets too large for your garden, it helps to know that you can cut it back hard.

→ Note: it’s part of the same family as poison ivy, so if you’re sensitive to that, wear gloves when handling sappy branches (risk of light dermatitis).

Propagation:

To get new smoke tree specimens, simply prepare cuttings from semi-hardened wood, or layer it.

Diseases and pests:

Very resistant, your Cotinus isn’t vulnerable to many diseases. If weakened by drought or overwatering, it might get infected by verticilium wilt, leaf spot, and rust. It also doesn’t seem to attract parasites and pests.

Interesting species and cultivars

Cotinus coggygria

This variety is particularly interesting, especially thanks to its purple-leaved cultivars such as the ‘Rubrifolius’ (deep purple with silvery overtones) and ‘Grace’ (light purple). The most famous is Cotinus coggygria ‘Royal Purple’ which has red-rimmed leaves.

• The ‘Grace’ cotinus is shown above, near the beginning of this article.

Cotinus obovatus

Similar enough to its cousin C. coggygria, C. obovatus is different in that it grows taller: it reaches heights of 30 feet (10 m).

• To be sure of good leaf colour, buy purple-leaved plants as named cultivars propagated from cuttings or grafts, because seed-raised plants vary and late spring not inherit the parent’s depth of colour.
• ‘Grace’ is a hybrid between C. coggygria and C. obovatus, so it is more vigorous than most coggygria cultivars and wants extra elbow room.
• C. obovatus comes from limestone country, and it copes well with chalky, alkaline ground where other feature shrubs sulk.
• C. obovatus can be trained up on a single trunk as a small tree, while C. coggygria naturally makes a multi-stemmed shrub.

Which Cotinus to choose

The genus is grown above all for its foliage, and the differences between the named cultivars and the two species come down to leaf colour and final size.

Whichever you pick, full sun and well-drained soil are what bring out the colour.

Named Cotinus cultivars compared

Beyond leaf colour, the cultivars sold in garden centres differ widely in final size, from knee-high shrubs for pots to small trees. This table sets the most commonly available ones side by side so you can match one to the space you have.

Landscaping uses and companion plants

Versatility is the key word for Cotinus: it is beautiful as a standalone and in groups, in a shrub bed or as part of a freestyle hedge.

Have fun pairing it with other purple-colored plants, creating a beautiful camaieu in your garden with Physocarpus opulifolius ‘Diabolo’ and Berberis thunbergii ‘Atropurpurea’ or ‘Harlequin’.

If you’d like to try alternating deciduous and evergreen foliage shrubs, Photinia, privet, Escallonia and Silverberry are great candidates.

• Where possible, site plumed plants such as Cotinus or ornamental grasses so that low sun backlights them, since backlighting catches the fine hairs and greatly enhances the smoky, hazy effect.
• As a general planting principle, group plants with matching water needs: beneath a drought-tolerant specimen, choose companions that also thrive in dry, well-drained soil rather than thirsty perennials requiring regular summer irrigation.
• The golden-leaved smoke bush Cotinus coggygria ‘Golden Spirit’ (‘Ancot’) is prone to leaf scorch in intense, hot sun, especially where soil dries out, so light afternoon shade suits it best.

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