It would be safe to say that most gardeners associate dogwoods, the genus Cornus, with the flurry of white- or pink-bracted flower smothering Cornus florida, C. kousa, C. nuttallii and their hybrids in spring. A few might thinks of the soft winter yellow of Cornellian cherry dogwood (C. mas) or even the magnificently tiered C. controversa ‘Variegata’. Probably fewer arrive at the ground-covering bunchberry (C. canadensis). A paltry number would picture the gray, or northern swamp, dogwood, Cornus racemosa.
Cornus is the type genus of the dogwood family, Cornaceae, which harbors an assortment of well-known garden plants, from Aucuba japonica in Japan to New Zealand’s Corokia cotoneaster. The genus Cornus comprises about 50 species, which cover a broad spectrum of sizes and shapes, from towering trees to spreading groundcovers to (in the semi-tropics) epiphytic shrubs. The common name is corrupted from dagwood, or daggerwood, revealing the chronicled use of its hard wood for skewers or daggers.
A few species offer substantial showy bracts surrounding a central corymb of flowers; however, this trait is far more the exception than the rule. Most dogwood species present upright clusters of small flowers in early spring, resulting in colorful crops of fleshy fruit. The fact that C. racemosa blooms late in the season, often not until mid-July, sets it apart and makes a case for broader use of this rugged yet handsome American native.
While hiking the reclaimed farmlands of northern Michigan as a boy, I became familiar with this shrub, standard fare in hedgerows and forest margins. It was not until much later that I matched a Latin name to it, recognizing the genus’s signature paired leaves with prominent parallel veins.
In the central highlands of the Great Lakes State, C. racemosa grows as a small suckering shrub to five feet or more and provides important browse for deer and nesting habitat for a large number of bird species. The ovate leaves take on muted tints of red and orange in autumn, just as substantial crops of white berries held on red pedicels (stems) begin to ripen. The berries are carried throughout much of winter, or until hungry birds devour them. This fruit follows a tardy but prodigious offering of white flowers in mid-July. Having more than one specimen of this species in a general vicinity will result in more bountiful crops of fruit.
Across eastern Canada, the eastern states and west to Oklahoma, C. racemosa can be found growing in a variety of habitats, from sandy full-sun sites to moist shaded locations. I had always considered this species only as a multi-stemmed shrub until a garden visit in the Minneapolis area opened my eyes. There I encountered specimens trained as single-stemmed trees. I could not have been more impressed with their form and presence, smothered as they were in creamy white at a time of the year when little else was flowering.
When a plant possesses as wide a natural distribution as C. racemosa, there’s promise of naturally occurring forms distinct enough in foliage, flower or fruit to encourage their use in breeding programs. Thus, several named cultivars exist in the trade, including a series Counties of Ohio, whose members are named for, well, counties in Ohio.
Flowers by Kevin Kenny/CC BY-SA 2.0