Cornus nuttallii Audubon

‘Noblest of the cornels’ (Bean 1976), Cornus nuttallii has inspired superlatives ever since Thomas Nuttall’s first encounter with the tree that would come to bear his name. Arriving in Fort Vancouver, Washington State at the end of September 1834, Nuttall was struck by the magnificent appearance of some fine trees with ‘large, oval, acute lucid green leaves, which, taken with the smooth trunk and unusually large clusters of crimson berries’ led him to assume it was an unknown species of Magnolia until he diagnosed Cornus from the flower buds, ‘already advanced for the coming season’ (Nuttall 1849). His delight was complete when the following May the flowers appeared with an involucre ‘nearly 6 inches [15 cm] in diameter!’

In fact, the species had already been noticed in roughly the same locality in April 1825 by David Douglas, who had remarked on an abundance of smooth-barked Cornus with ‘great profusion of large white flowers’ in the the pine forests by the Columbia River (Douglas 1914), apparently without realising that the trees differed from their east-coast counterparts, Cornus florida. The tree was named for Nuttall by the ornithologist J. J. Audubon, who described it in the course of a discussion of the Band-Tailed Pigeon (Patagioenas fasciata Say, syn. Columba fasciata). Nuttall had observed large flocks of the birds feeding on the fruits in late autumn (Audubon 1838). In the Catesbian tradition of depicting birds with associated plant species (see the entry for Catalpa bignonioides), Audubon’s corresponding plate in Birds of America (1837, pl. 367) showed the new tree – simultaneously in flower and fruit – with two of the pigeons feeding on the berries; the Cornus itself was painted by Audubon’s collaborator Maria Martin.

Cornus nuttallii is indeed similar to the Eastern Dogwood, C. florida, but differs, as Nuttall observed, in that its inflorescences overwinter without the protection of enclosing bracts, which are not needed in the milder winters (see the discussion of bracts in the genus entry). The trunk is also distinctive: in contrast to the furrowed, often rather ‘reptilian’ bark of the eastern species, on larger trees the bark is characteristically smooth, having passed through a scaly condition seen on smaller stems. The involucre is usually described as four-to-six bracted, but up to eight bracts have been observed, particularly in the material grown in Britain in the early twentieth century (Prain 1910). On occasion the tree can be remontant (Sargent 1893), with a second, weaker floral display in autumn as reflected – perhaps inadvertently – in Audubon’s 1838 plate. Wild trees tend to form a single stem in forest conditions when they are pulled up to the light, becoming more shrubby in the shade. They are characteristically found at the edge of clearings or at forest margins, often growing one-sidedly outwards into the light (Lichthardt 1991).

Audubon sent seeds to Lord Ravensworth of Eslington Park, Northumberland, where seedlings were germinated and raised, so that by 1838 young plants could apparently be seen ‘in the vicinity of London and in [Ravensworth’s estate] near Newcastle-upon-Tyne’ (Audubon 1838). Nuttall himself also brought seed back with him when he finally returned to England in 1842, but reported that his plants were still only small after seven years’ growth (Nuttall 1849). The species seems to have reached Europe before it became widely available in America – indeed, this period is marked by increasing frustration on the part of New England gardeners at the the sluggish eastwards traffic in newly discovered material from the Pacific Northwest. Species known by repute such as Cornus nuttallii, Arbutus menziesii and Chrysolepis chrysophylla were all viewed as desirable prizes, but none was yet obtainable (Massachusetts Horticultural Society 1843).

When Cornus nuttallii did enter cultivation, it soon acquired a reputation for being extremely difficult to please, both in Britain and in the Eastern United States (Dirr 2009). The species tolerates neither winter frost nor cold summers, yet relies on year-round moisture at the roots, requirements that appear to be satisfied only within a rather confined area with a climate of the cool-summer Mediterranean-type (Köppen classification Csb). This is in effect a Mediterranean climate that is attenuated at both ends of the temperature scale, the summers not being hot (the warmest month mean temperature not exceeding 22°C) and the monthly mean winter temperature not below –3C°. Geographically, these conditions – and the species itself – occur around the rim of the southern Strait of Georgia (between Vancouver Island and the continental mainland), southwards through the cyclically fog-bound coastal forests of the Pacific seaboard, and (beyond the fog zone) onto the elevated slopes of the mountains further inland. The distribution stretches almost the full length of the state of California, including the Santa Cruz Mountains and the northern side of the Santa Lucia Mountains, extending into Los Angeles and even San Diego Counties. In the Sierra Nevada, it occurs as far south as the Greenhorn Range in Kern County. In these extreme southerly districts, however, the species becomes sporadic and local, its occurrence apparently coinciding with areas where the zonal mediterranean climate is tempered by warm-season precipitation (i.e. late-summer rain) (Raven & Axelrod 1978). These southerly populations, particularly at low altitudes, are nevertheless of potential horticultural interest as the source of ecotypes that may be suited to cultivation in more marginal (i.e. drier) conditions (see C. nuttallii ‘Pilgrim’).

The Canadian populations of Cornus nuttallii are associated almost exclusively with Coastal Douglas Fir Forest, of which the species is an important floristic component, while in California the tree grows as part of a Mixed Evergreen Forest community in association with Pseudotsuga menziesii, Pinus lambertiana, Lithocarpus densiflora and Quercus chrysolepis (average rainfall 635–1650 mm, some fog), and at higher elevations in Yellow Pine Forest with Pinus ponderosa, P. jeffreyi and Quercus kelloggii (average rainfall 635–200 mm, partly as snow) (Munz & Keck 1973). A disjunct population, in steep decline since the mid 1980s, occurs in the Clearwater and Nez Perce National Forests, western Idaho, presumbly a remnant of a broad continuous pre-glacial distribution. The survival of the Idaho population is attributable to the unusual, moist and moderate microclimate of the river ravines in which it grows (Lichthardt 1991).

Where these stringent environmental conditions cannot be adequately approximated, Cornus nuttaliii will struggle as a garden specimen. In the early twentieth century, seventy years after its introduction, the tree remained uncommon in Britain, where its flowering and fruiting occasioned considerable excitement (Prain 1910; Bean 1915). The years 1910–1915 saw an improvement in flowering, though based on his subsequent experiences at Kew, Bean reported that the plants were not long-lived (Bean 1976). Even apparently thriving plants that had flowered annually for twenty years might undergo sudden deterioration, and Bean lamented that ‘unless a better form is introduced, it is a species that must be counted as short-lived in British gardens’.

Cornus nuttallii remains challenging to grow outside its natural range. It will always be a prized possession of those fortunate growers who are able to meet its needs, but is likely to remain out of reach of many others. Happily, the development of less demanding hybrids with C. florida (see Cornus × transamericana) has made many of its most elegant characteristics available to a wider public. Considerations to be taken into account by those who would attempt to grow the straight species are site (a sheltered position in sun) and drainage (soil that is retentive but not heavy), though practical experiences are decidely mixed – Graham Stuart Thomas (1992) recorded that the best tree he knew grew on poor gravelly soil. Attention to irrigation, particularly while young, is also important. When happy, C. nuttallii can make a substantial tree even in British conditions, as seen at Ray Wood, North Yorkshire, where it thrives on the moist but well-draining sandy soils (J. Grimshaw, pers. comm. 2025). A celebrated early twentieth-century specimen thrived in similar conditions on sandy loam in the garden of the cornus enthusiast B. E. C. Chambers at Grayswood Hill, Surrey – on a sloping, south-west-facing site 90 m asl, this garden was ideally situated to avoid late frosts (Bean 1976).

Propagation by seed is possible, though seed-raised plants have been found not to do well in Britain, and the specialist Junker Nursery grafts it onto stocks of Cornus kousa for improved environmental tolerance (Junker 2023). Layering is not commonly attempted, but it is worth noting that wild plants have been observed to root at the nodes (Lichthardt 1991).

The greatest threat to C. nuttallii is the disease Dogwood Anthracnose caused by the fungus Discula destructiva discussed in more detail in the genus entry The symptoms are leaf spot, leaf margin necrosis and stem canker, as well as twig dieback. In North America, powdery mildew caused by the fungus Erysiphe pulchra can be a serious problem, particularly in humid districts with warm days and cool nights. Commercial nurseries rely on fungicide sprays, but the problem can be partly addressed by optimising air circulation through siting and judicious pruning.