UT Gardens' Plant of the Month for May 2008:

Kousa Dogwood

Submitted by Becky Koepke

Kousa dogwood, also known commonly as Chinese or Japanese dogwood is an exceptional small landscape tree with four-season interest. Botanically named Cornus kousa, this dogwood produces a multitude of showy, long-lasting, white flowers in late spring, after our common flowering dogwood (Cornus florida) has finished blooming. Also, kousa dogwood is multi-branched, creating an interesting texture. Finally, older trees have a very decorative, mottled bark.

As the kousa’s blooms fade in the spring, the dogwood's attractive dark-green or variegated foliage is revealed. Globular green fruits then appear and turn to pink, then dull red in September, resembling large solitary upright raspberries on a two-inch peduncle.

Fruit set is usually light, being sparsely scattered above the foliage, and readily eaten by birds and squirrels when ripe. Fall foliage can be a dark red or chartreuse, depending on the amount of sunlight received throughout the season.

One standout feature of kousa dogwood is its incredible resistance to the diseases that plague flowering dogwoods (Cornus florida) and often result in their death. Kousa dogwood also has a higher tolerance for alkaline soils.  

Native to eastern Asia, kousa dogwood is hardy in zones 5 -8 and grows to about 20 feet tall and 20 feet wide. It prefers full sun to partial shade and moist, well-drained, acidic soils, but it is adaptable to other poor soil conditions. The tree is susceptible to leaf-scorch in hot, dry weather; so, it is best to give it extra water in those conditions.

Chinese dogwoods make great specimen trees. Use them alone or in a grouping, or near other contrasting trees. Given their short height at maturity, these dogwoods are often recommended for planting underneath power lines.

Three great selections can be found scattered throughout the UT Gardens in Knoxville. They should be available at many nurseries throughout the state:
 
*C. kousa "Wolf Eyes" is a unique variegated cultivar with crinkled, creamy-edged foliage. Unlike many other variegated varieties, the variegation stays true no matter if the tree is placed in sun or shade. In the fall the foliage turns various shades of pink to red. 

C. kousa "Blue Shadow" has rich blue-green color foliage in the summer turning purple for the fall. 

Becky Koepke is a graduate research assistant in the University of Tennessee Department of Plant Sciences. She is studying under Dr. Sue Hamilton, associate professor and director of the UT Gardens. The UT Gardens are a project of the Tennessee Agricultural Experiment Station and in 2007 the Gardens are celebrating their Silver Anniversary. On the Web at http://utgardens.tennessee.edu

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Contact:

Patricia C. McDaniels, (865) 974-7141