Silky dogwood shows its colors

Each month, UT Gardens at the University of Tennessee suggests a Plant of the Month to garden writers and gardeners in the state. The January, 2020 featured plant is Silky Dogwood (Cornus amonum), a deciduous shrub native to the eastern U.S. that has small white flowers in late spring and clusters of blue berries in late summer and fall.

The silky dogwood that’s featured this month, though – a variety called ‘Cayenne’ — shows its best feature in winter, when the stems can stand out in bright, beautiful red against an otherwise brown landscape, or (if we’re lucky) with a background of fresh snow.

“Red twig dogwoods are hard to beat for their dramatic colorful show of stems in the winter,” says Jason Reeves, a research horticulturist at UT Gardens in Jackson, TN. Common cultivars include ‘Baileyi,’ ‘Cardinal,’ ‘Isanti,’ ‘Winter Flame’ and others. Unfortunately, he says, these are susceptible to canker/twig blight, and can be short-lived in the South.

‘Cayenne,’ however, is not affected by stem canker like many of the other species. It was brought to light in 2011 by the renowned horticulturist Michael Dirr, who spotted the bright red twigs growing in a roadside swamp in Virginia.

Like other silky dogwoods, ‘Cayenne’ is a multi-stemmed shrub that spreads by suckers, Reeves says. It is hardy in zones 4 – 9, thrives in full sun to partial shade, and grows best in good garden soil where supplemental water can be provided during dry periods. The bright stems turn gray after a couple of years as the bark matures, so Reeves suggests cutting back older stems close to the ground in late winter or early spring. This encourages strong, new red stems to spring forth.

The plant makes a good shrub border, and in moist areas it can form a dense colony and provide effective erosion control. If it’s not pruned, the shrub can reach 6 – 8 feet tall and 8 – 10 feet wide in three to five years, Reeves says.

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The UT Gardens includes plant collections located in Knoxville, Crossville and Jackson, TN. Designated as the official botanical garden for the State of Tennessee, the collections are part of the UT Institute of Agriculture. They are open during all seasons and free to the public. To learn more, visit the UT Gardens website.