Red-twig Dogwoods: a Shrub for All Seasons
(Editor's Note: This article was originally published on August 2, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
Shrubs and trees provide the backbone to any garden. Evergreen material is ideal as they provide year-round appeal. Shrubs like rhododendrons and mountain laurel are even better as they also provide flowers. Of course, we all don't live in a climate where broad-leaved evergreens are an option. For northern gardeners, we have more to choose from among deciduous material, but finding such material that can provide all season interest can be a challenge. Thankfully, there is one shrub that immediately comes to mind; the red-twig or red-osier dogwood. Whether you grow the wild form or the many cultivated selections, this shrub will provide blossoms, attractive foliage, oftentimes good fall colour, a modest fruit-display and attractively-coloured twigs that show to their full glory during the winter months.
Red twig dogwoods belong to one of three species; the American Cornus stolonifera (aka C. sericea), the European C. sanguinea and the Siberian-northern Chinese species C. alba. In the wild, C. stolonifera and C. alba will reach about 3 m while C. sanguinea can reach 4 m. All are well adapted to wet soils, often growing semi-submerged along streams and pond margins. They have small clusters of white flowers in late spring followed by white fruit on C. stolonifera and C. alba or purple-black on C. sanguinea.
Cornus sanguinea is the least common of the three, at least in North America. Less horticultural selections have been made from this species than the other two. While reasonably hardy (zone 4) the other two are even tougher (zone 2-3). The wild form of C. sanguinea has somewhat dull brownish-green twigs that are dark red on the sunny side; not as outstanding as C. alba or C. stolonifera. However, the European species does have one advantage over the other two; it has fragrant flowers. One of the most spectacular selection made from C. sanguinea is ‘Widwinter Fire'. During the summer, this selection is rather unassuming, but the fall colour is brilliant golden-yellow and the winter twigs glow, being yellow-orange with red tips. There are some 20 cultivars from this species, most selections being based on the winter twig colours. However, these selection seem to be grown primarily in Europe. In North America, we grow mostly C. stolonifera and C. alba.
The wild forms of C. alba and C. stolonifera are so similar that only a botanist can appreciate the difference. Over the years there have been many selections made from each. It is probably easiest simply to describe the cultivars than worrying about the species from which they were developed., especially when you consider a given cultivar name may be applied to either species. Today, there are over 30 cultivars developed from these two species, with new ones added every few years. The main trend these days is the selection of smaller forms which are more in scale with today's smaller gardens.
Details of Cornus stolonifera: blooms, fruit and fall-colour
Many of the oldest selections are still very popular today. The only thing to remember is that these will grow 2-3 m in height and even wider so they will require some space. The old standard red-twigged cultivar is ‘Siberica' (aka ‘Westonbirt'). This one contrasts beautifully with the yellow-twigged ‘Flaviramea' and the purple-red twigged ‘Kesselringii'. Newer, winter-interest versions of these are more disease resistant and include ‘Cardinal' (bright red twigs), ‘Cheyenne' (dark red twigs), ‘Bud's Yellow' (yellow twigs) and ‘Winter Flame' (yellow, orange and red twigs).
Two examples of cultivars grown for their winter twig colour are 'Flaviramea' and 'Cardinal'
‘Elegantissima' is the common variegated dogwood with grey-green leaves and irregular white margins. This one has lovely dark red stems but the autumn colour is rather drab. 'Siberica Variegata' has brighter red twigs and leaves with a thin white margin. ‘Spaethii' has bright green, yellow-edged leaves and red twigs with much better fall colour. ‘Gouchaultii' is similar but has some pink highlights among the yellow edges. ‘Aurea' has bright gold foliage all summer and bright red twigs in winter. Newer, even hardier gold-leaved selections are ‘Morden Amber' with dark red twigs and ‘Prairie Fire' with orange-red twigs. ‘Sunshine' is a newer cultivar which has wide, irregular yellow margins or entirely yellow leaves and red-twigs. This one will burn in full sun so grow it in part shade where the leaves will become bright chartreuse in summer. ‘Silver and Gold' is a white-edged, variegated sport of ‘Flaviramea' with yellow winter twigs. ‘White Gold' is quite similar but less vigorous.
Some cultivars selected for their foliage include 'Elegantissima', 'Spaethii', 'Silver and Gold' and 'Aurea'
As mentioned earlier, many of the newer selections being developed have a more compact habit. Perhaps the most popular of these is ‘Bailhalo' (aka ‘Ivory Halo'), a 1.5-2 m version of ‘Elegantissima'. Even more dwarf is the new ‘Cream Crackers' which only reaches 80 cm. ‘Hedgerow's Gold' is a compact (1.5-2 m) selection with yellow-variegated leaves and red twigs. A dwarf version of ‘Sunshine' is ‘Garden Glow' (1.2-1.6 m). Like ‘Sunshine', it also appreciates some shade.
Among the plain-green, compact selections grown for their winter twigs are ‘Isanti (1.75-2m) with dark red twigs, ‘Siberian Pearl' (1.5-2 m) with dark red twigs and particularly abundant fruit production, ‘Arctic Fire' (1.2 m) with bright red twigs, ‘Kelseyi' (60-100 cm) with red twigs and notable flower production and ‘Rosco' (aka Kelsey's Gold', 60-100 cm) with yellow to chartreuse foliage and red twigs.
As for the culture of these plants, they are generally easy as long as the soil does not get too dry. They certainly can tolerate wet feet if that is an issue in your garden. They will grow in full sun to reasonable shade, but variegated versions may not develop the best colours if grown in too much shade, nor will winter twigs be as bright. The main cultural practice is pruning. The newer twigs develop the best colour and as the stems age, the colours start to fade. It is best to remove about a third of the older branches yearly. This will keep the plants from getting too bushy and help encourage new basal shots which will have the brightest winter colour. These shrubs may be propagated from softwood, semi-hardwood or hardwood cuttings. This ease of propagation has kept the retail price of these shrubs relatively inexpensive.
As you can see, the ‘red-twigged' dogwoods are quite varied and regardless the size of your garden, there are a few selections which would make admirable additions for year-round attraction.
I would like to thnak the following people for the use of their pictures: Growin ('Midwinter Fire' and 'Spaethii'); mrporl ('Flaviramea'); hczone6 ('Silver and Gold'); Evert (opening photo of 'Siberica Variegata') and chicochi3 ('Ivory Halo')