June plant of the month: Smoketree or Smokebush Posted: Thursday, June 10, 2010 4:52 pm
By: Submitted by Carol Reese Truthfully, woody plants reported to have purple foliage are rarely purple. The colors are probably better described as wine, maroon, aubergine, or burgundy. Still, the word purple is just fun. It’s one of those words that sounds weirder and weirder the more you say it.
The beauty and effect of purple foliage is influenced by climate, so plants that look wonderful in New England or the northwest may look tired and ugly in our southern heat. I found that to be true of the weigela ‘Wine and Roses’. I’d seen it looking glorious in northern gardens, but in our hot summer, it turned the color of tired coffee.
Unfortunately the same is true of most forms of purple smoketree, also called smokebush (Cotinus coggygria). The foliage is glorious for the first few weeks of summer, but soon it fades and looks tortured by the sun. This is not true of a cultivar named ‘Grace,’ ‘Grace’ is the result of a cross between Cotinus coggygria which originates from Eurasia, and Cotinus obovatus, which a small tree native to the southeastern United States. This plants does not have the rich dark purple of it’s Eurasian parent, but rather is a lovely deep mauve that flashes reddish leaf undersides. It does have large misty blooms, the feature that appears to be purple “smoke” and which gives the plant its common name.
Grace’ also differs in that she wants to be more like her tree parent in stature. I laughed when I saw the tag on some lately that read that the plant would reach twelve feet. I’ve seen it grow ten feet in a single season!
I don’t see anything wrong with that. I think a purple tree with smokey purple flowers is a very cool addition to the landscape. Some of my gardening friends are determined to manage it as a shrub, and cut it back severely each year, which makes it throw out even more gorgeous foliage, but I like to let it go. If for no other reason, I am eager to evaluate its potential as an ornamental tree, large and fast growing enough to offer quick shade.
‘Grace’ is very easy to grow, requiring nothing more than a sunny site and well drained soils.
Carol Reese the University of Tennessee Extension Ornamental Horticulture Specialist for the Western District. Her office is located in the West Tennessee AgResearch and Education Center in Jackson. The UT Gardens located in Knoxville and Jackson are part of the UT Institute of Agriculture and their mission is to foster appreciation, education, and stewardship of plants through garden displays, collections, educational programs, and research trials. The gardens are open during all seasons and free to the public. Published in the Press 6/8/10 , | 
