by Penny Pawl, UC Master Gardener of Napa County
One of my favorite drought-tolerant plants is the smoke bush (Cotinus coggygria). This wonderful bush is sometimes called smoketree. It is native to southern Europe and temperate parts of Asia.
What is so notable about this bush is the brownish/maroon color of the leaves and the flower brackets. When mature, the brackets appear above the leaves and give the appearance of rising smoke.
This plant is not to be confused with the smoke tree (Psorothamnus spinosus) which is native to Arizona and in the pea family.
Smoke bush grows best when planted in poor or rocky soil. It needs good drainage. I planted two some years ago and have not watered them other than to get them established. They seem to do well on whatever rain they get. Another plus is their resistance to oak root fungus.
Smoke bush grows as wide as it is tall, reaching 15 feet in both directions if not pruned. It is multistemmed.
So when should you prune this wonderful plant? I have been trying to determine the best time. I am pretty sure I did it wrong last year as I saw no smoke this past summer.
The flowers and smoke come on older stems. The smoke parts are plumes which come after the blooms and last for several weeks. In fall the leaves turn a beautiful red and gold before they drop.
If you plan to prune, I suggest doing it when you can see the stems. Next year I plan to wait to prune until the smoke is gone. I'll see if that timing produces more flowers and plumes the following spring.
I have been trying various methods of propagating this plant without much success. It is usually propagated from cuttings. I have tried putting short stems of old wood in a cloner (a machine that washes the stem end constantly with water). I've tried to propagate cuttings in a regular planting mix. I have yet to try air layering, which involves wrapping a stem, still attached to the mother plant, with damp moss in hopes that it will produce roots.
The original plants had stems that rooted in the soil around the plant. I think a couple more stems may have rooted on their own. I will dig them up and see what has happened there. Since they are drought tolerant, watering may be too much for them.
Because of its beauty, leaf color and drought tolerance, smoke bush is an excellent plant to consider for your garden.
The smoke tree (Psorothamnus spinsus) is native to Arizona, Baja and the southernmost part of California. It is common in Joshua Tree National Park and. has adapted well to the desert. The leaves are small and short lived. The violet flowers are a source of nectar for honey.
The smoke tree will grow to about 20 feet tall. It has multiple branches that are spiny and without leaves most of the year. Somehow these twigs produce enough energy from the sun to feed the tree. Because they have evolved to thrive in the desert, I am not sure if they would do well in Napa Valley.
Workshop: Napa County Master Gardeners will lead a workshop on “The Art of Raising Succuluents” on Sunday, December 5, from 1 pm to 3 pm, at the Yountville Community Center, 6516 Washington Street, Yountville. Discover how to care for and design with these colorful, unthirsty plants in your garden or on your patio. Attendees will get plant starts to take home. Yountville residents: $16; Non-residents: $18. Free to Golden Ticket members.To register, visit Online registration (https://bit.ly/3HXas5K)or telephone the Parks & Recreation Department at 707-944-8712.
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