The NCSU Arboretum (now the JC Raulston ArboretumClear nights with glittering stars and frosty, nippy mornings are sure signs that winter is here. The broad green leaves of summer have become dried, historic documents on the ground or sit layered as mulch on the garden's borders. All of nature's bare bones are visible in the form of the tracery of branches and the sculpture of trunks and limbs. What a change in the landscape winter brings and what a wonderful opportunity to garden with striking color and form. There are thousands of plants that shine in winter, both evergreen and deciduous. Two especially striking plants for winter color are the shrubby Dogwoods: Cornus alba, the Tatarian Dogwood, and Cornus sericea, the Redosier Dogwood.
Both of these Dogwoods are special because they have brilliantly colored red or yellow stems in winter that add bold shades to the landscape when many plants are garbed in muted tones of brown and grey. Both Dogwoods additionally bear clusters of small, whitish flowers in early summer which mature into bluish-white fruit but winter is generally their showiest season. The green summer foliage can turn to beautiful shades of purple and red in the fall but this is a very variable trait. There is often confusion between these two Dogwoods because both have a number of cultivars with red colored stems while only two cultivars of C. sericea have bright yellow stems.
Cornus sericea is native to eastern North America, from Canada to Kentucky and can be seen growing in low, wet areas and other abandoned, woody sites. It is hardy throughout the southeastern US from the coast to the mountains. This Dogwood will reach 5 to 9 feet in height with an equal or greater spread. An older botanical name for this plant was C. stolonifera, referring to its underground, spreading, stolons. The plant will spread into a mounded colony of many upright stems with short, horizontal branching. It can be a bit invasive as it is a vigorous plant that grows rapidly. However, this can be advantageous in difficult sites. It is well-adapted to a broad range of soil conditions in the landscape and will tolerate everything from swampy to droughty conditions. Redosier Dogwood is most striking in full sun where stem color is best developed and most easily seen. It is easily propagated from rooted cuttings taken anytime during the year when leaves are on the stems, or from seed layered in moist peat and held at 40F for 2 to 3 months.
There are several red-twigged cultivars of C. sericea but perhaps the most well-known and readily available cultivar of this plant is 'Flaviramea' (sometimes seen as 'Lutea'), the Yellow Twig Dogwood. The stems of this cultivar are a vibrant canary yellow which glow like lasers in the landscape. They are especially beautiful when grown near a red-twigged cultivar or in front of a dark, evergreen Holly or Mahonia. As with all of the colored stem Dogwoods, care is needed to avoid misplacing this bold beauty and drowning out other, quieter garden voices. Recommended red twigged cultivars of Redosier Dogwood include: 'Cardinal' and 'Isanti', both introductions from the Minnesota Landscape Arboretum. There are also cultivars with variegated foliage which add interest during the summer. One excellent variegated cultivar is 'Silver and Gold'. 'Silver and Gold' is an introduction from the Mt. Cuba Center for Research on Piedmont Plants in Pennsylvania. It was selected from a mutation found on a plant of 'Flaviramea'. 'Silver and Gold' has bright yellow stems and a creamy white margin on the leaves.
Cornus alba, the Tatarian Dogwood, is a native of Siberia and Korea. There are no yellow stemmed cultivars of this Dogwood but there are many red stemmed cultivars, several of which exhibit a range of interesting foliar variegations during the spring and summer. It is very similar in size and habit to Redosier Dogwood, although not quite as potentially invasive. Nonetheless it is very vigorous and can still take over an area from other less rampant plants. It is also adapted to a range of soils but prefers moist, well-drained sites in full sun. To get the best stem color, which develops on young, vigorous growth, remove older and larger branches by cutting these back to 6 to 12 inches in late winter each year. This will also help to control its spread. C. alba is somewhat more cold hardy than C. sericea but more importantly, is significantly less well-adapted to the hot, humid summers of the Piedmont and coastal plain. It is therefore probably a better choice for the mountains, while C. sericea would be more appropriate for the Piedmont and Coastal Plain. It can be propagated like C. sericea but cuttings can be taken at any time of year and should root readily under mist.
Good cultivars of C. alba include:'Argenteo-marginata' (or 'Elegantissima') which has leaves with creamy margins and soft, grey-green centers that are lovely against its bright red stems, even in summer, 'Sibirica' has carmine stems and bluish fruit and may be somewhat less invasive than others, 'Spaethii' has leaves with bold yellow borders which hold their color better than other cultivars through the summer season.
Whatever cultivars of these Dogwoods find their way into your garden, they will paint the landscape with bold, vertical strokes of red and yellow. There is little else more arresting in a winter garden than their spears of scarlet and gold stems piercing a blanket of white snow or framed by the black-green of a holly hedge. At the NCSU Arboretum (now the JC Raulston Arboretum), these Dogwoods punctuate the Piedmont winter in the west Arboretum and the Southall garden. Come brave the chilly weather to see their brilliant colors in the glow of winter's light. br>