PLANT OF THE MONTH
July, 2009
Plant of the Month Feature
by Marion Johnson
Arboretum Roots Board Member
Master Gardener
Cotinus coggygria
Smoke Tree
During the spring and summer if you walk along the red brick pathway at the Bickelhaupt Arboretum you may notice near the Mercy Hospice Herb Garden, a group of small trees with panicles of wispy dark pink or lavender flowers which give the effect of a cloud of smoke. These are varieties of Cotinus coggygria, commonly known as "Smoketree." Leaves of these trees have beautiful colors in spring which change to brilliant hues in the fall.
One of the varieties, Cotinus coggygria 'Purpureus,' is a slow growing, open-crown, round small tree which eventually reaches to almost 15 feet tall. In the spring the leaves emerge purple then fade to dark green in the summer. The leaf color in the fall ranges from yellow to orange and brilliant red-purple. Also of interest is the black, showy multiple trunk.
Another variety, Cotinus coggygria, 'Young Lady,' is a new and exciting variety from the Netherlands. 'Young Lady' is unique among Smoketrees because it blooms pink as a young shrub covering every inch of the plant from June till August. The foliage starts out blue-green. In the autumn, the leaf color turns yellow, orange and red. In a container it looks like a poodle in a pot with its frothy blooms covering every inch of the plant!
Golden Spirit 'Ancot' is a cultivar that is distinctive because of its unusual golden foliage. The yellow leaves suffused with green retain good color throughout summer, and turn amber, burgundy, scarlet and green in fall.
A small Smoketree, 'Nordine' is the hardiest of the cultivars. It was selected to be in the Morton Arboretum in Lisle, Illinois for its color and is located on the southside of the Smoketree collection . The leaves hold purplish red color well into the summer, changing to yellow to orange-yellow in the fall. Roy Nordine, former propagator of the Morton Arboretum, was the first curator of the collections and original Board of Directors member of the Bickelhaupt Arboretum.
Smoketrees grow best in a well-drained soil in a sunny location. They grow asymmetrically and lean toward the light in a partially sunny area so it is best to plant them in full sun. Though sometimes short-lived in rich soil, Smoketrees grow well in dry rocky soil.
The wood and bark chips from the Smoketree have been used since the Middle Ages. When mixed with tin and alum mordants a clear yellow dye is formed. Different mordants produce more hues, such as pink and an orange-tan. When mixed with indigo, the dye becomes a beautiful green.
I chose the Smoketree because of the many interesting and colorful changes in the flower and leaf color from spring through late fall. There is another reason. Many years ago I heard about Smoketrees from my mother. The story she told took place in Schrobenhausen, Germany about 100 years ago when my mother was a young girl. In the yard next to her house grew a Smoketree. One spring evening, when the Smoketree was in full bloom, a young man, who was courting her sister, decided to climb a ladder up to her sister's bedroom window. My feisty grandmother found out about this and yelled, "Fire, Fire!" The young man fell off the ladder, but fortunately did not break anything - that I know of! I am sure that he did not try it again. In this century the lovers would be text messaging which may a lot safer!
About the Author: Marion Johnson was an instructor at Mount St. Clare College who retired after 25 years as Professor emerita in Chemistry. She is a Master Gardener and enjoys volunteering at Bickelhaupt Arboretum in numerous programs/activities and as a Roots Community Board Member.The arboretum is very pleased to have Marion as a volunteer and Roots Community Board member.