Cornus obliqua Raf. — Blue colonel dogwood

Introduction

Blue colonel dogwood is a deciduous shrub or small tree of wet woods, wet meadows, ditches, marshes, and stream banks across much of eastern and north-central North America. Its blue fruit resembles that of C. amomum, but the leaves tend to be narrower with pale lower surfaces and rigid appressed hairs. The species belongs to Subgenus Thelycrania (Deasy et al. 2026).

Some treatments have reduced C. obliqua to C. amomum ssp. obliqua, and intermediates occur where the two species meet. Modern phylogenomic work nevertheless supports a distinct C. obliqua lineage, recovered as sister to western C. glabrata. Tree TSAR additionally routes the historical schuetzeana name cluster here on type and concept grounds rather than following POWO’s current placement under C. amomum.

Cornus obliqua is also one parent of the named natural hybrid C. × arnoldiana with C. racemosa. Older sources may describe that hybrid as involving C. amomum because of the former broad treatment of C. obliqua.

Horticultural and Agricultural Uses

Blue colonel dogwood is most useful in large naturalistic plantings, wetland margins, and streamside landscapes. It tolerates poorly drained soils and provides blue fruits for seasonal interest and wildlife, but its loose spreading habit is less suited to formal small gardens (Deasy et al. 2026).

The cultivar ‘Powell Gardens’ has been selected for compact growth, strong autumn color, pale indigo fruit, and dark winter stems. Such selections demonstrate horticultural potential without implying botanical infraspecific recognition.

Conservation Concerns

Trees and Shrubs Online lists Cornus obliqua as Least Concern. Its range extends across a broad part of eastern and central North America, and the species is not presently considered globally threatened (Deasy et al. 2026).

Locally, wetland loss and stream modification can reduce habitat. Accurate identification is also relevant to conservation inventories because records can be filed under C. amomum when plants are intermediate or when older taxonomic concepts are followed.

Additional Information

Trees and Shrubs Online (opens in a new tab) - Detailed modern account, identification, and cultivation.
Plants of the World Online (opens in a new tab) - Accepted Kew species page; its synonym placement differs from Tree TSAR for the schuetzeana cluster.
Flora of North America (opens in a new tab) - North American description and distribution.

References and Further Reading

Deasy M, Crowley D, Aldridge J, Chişu R (2026) Cornus obliqua. Trees and Shrubs Online. Link (opens in a new tab)

Royal Botanic Gardens, Kew (2026) Cornus obliqua Raf.. Plants of the World Online. Link (opens in a new tab)

Lindelof K, Lindo JA, Zhou W, Ji X, Xiang Q-Y (2020) Phylogenomics, biogeography, and evolution of the blue- or white-fruited dogwoods (Cornus) - Insights into morphological and ecological niche divergence following intercontinental geographic isolation. Journal of Systematics and Evolution 58(5): 604-645. Link (opens in a new tab)

Du Z-Y, Xiang Q-Y, Cheng J, Zhou W, Wang Q-F, Soltis DE, Soltis PS (2023) An updated phylogeny, biogeography, and PhyloCode-based classification of Cornaceae based on three sets of genomic data. American Journal of Botany 110(2): e16116. Link (opens in a new tab)

Murrell ZE, Poindexter DB (2016) Cornaceae. In: Flora of North America Editorial Committee (eds) Flora of North America North of Mexico, vol. 12. Oxford University Press, New York and Oxford. Link (opens in a new tab)