Cornus kousa Bürger ex Hance — Japanese kousa dogwood

Introduction

Japanese kousa dogwood is a deciduous East Asian flowering dogwood celebrated for its four large pointed bracts, strawberry-like red compound fruits, exfoliating bark on older plants, and reliable autumn color. It occurs in montane forest, mixed woodland, valleys, and streamside habitats, and is generally more adaptable in temperate cultivation than the superficially similar North American C. florida (Xiang & Boufford 2005; Deasy et al. 2026).

The resemblance to C. florida masks a deep phylogenetic distinction. Cornus kousa belongs to the East Asian subgenus Syncarpea, whose compound fruits contrast with the separate drupes of New World Cynoxylon. Genomic estimates place the divergence of these two major Benthamidia lineages deep in the Paleogene, so the two species are ecological and horticultural analogues rather than close sister species (Du et al. 2023).

Tree TSAR recognizes ssp. kousa and ssp. chinensis. The latter is morphologically subtle but geographically structured, and both population-genetic and cultivar-level genomic work support meaningful differentiation within the broad species (Nowicki et al. 2020; Moreau et al. 2024). Cornus kousa also serves as a parent of three named nothospecies in Tree TSAR: C. × rutgersensis, C. × elwinortonii, and C. × haddenii.

Horticultural and Agricultural Uses

Cornus kousa is one of the most important ornamental dogwoods in temperate horticulture. It is valued for a long season of interest and for generally strong performance in gardens where C. florida can be unreliable. Hundreds of cultivars and trade selections emphasize bract size and color, compact or upright habit, variegated foliage, fruiting, and autumn color. These selections are horticultural clones and should not be confused with the two accepted botanical subspecies (Deasy et al. 2026).

The species prefers fertile, moisture-retentive but well-drained soil and usually performs best with good light where summers are not excessively hot or dry. It is relatively resistant to dogwood anthracnose and has consequently become a major breeding parent for disease-tolerant interspecific dogwoods. Fruits are edible; in China they have also been used to make wine, although C. kousa is cultivated far more widely as an ornamental than as a crop (Xiang & Boufford 2005).

Named cultivars are propagated clonally. Seed is appropriate for breeding and conservation because it preserves recombination, but seedlings vary markedly and do not reproduce cultivar traits.

Conservation Concerns

Cornus kousa is assessed as Least Concern, and Kew’s predictive model likewise treats the species as not threatened at the global scale (Royal Botanic Gardens, Kew 2026). Its wide East Asian distribution and extensive cultivation contribute to that overall security.

Cultivation does not replace conservation of wild population structure. Genomic studies have detected geographic differentiation among Japanese, Korean, Chinese, and other populations, and ssp. chinensis itself spans a broad Chinese range with an unusual extension to Taiwan and the southern Nansei Islands. Provenance-rich seed collections therefore remain important even for a globally common ornamental species (Nowicki et al. 2020; Moreau et al. 2024).

Additional Information

Trees and Shrubs Online (opens in a new tab) — Extensive species, subspecies, cultivar, and horticultural treatment.
Plants of the World Online (opens in a new tab) — Accepted species, two subspecies, distribution, and conservation data.
Flora of China (opens in a new tab) — Regional taxonomic treatment.

References and Further Reading

Deasy M, Crowley D, Aldridge J, Chişu R (2026) Cornus kousa. Trees and Shrubs Online. https://www.treesandshrubsonline.org/articles/cornus/cornus-kousa/ (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. https://doi.org/10.1002/ajb2.16116 (opens in a new tab)

Moreau ELP, Medberry AN, Honig JA, Molnar TJ (2024) Genetic diversity analysis of big-bracted dogwood (Cornus florida and C. kousa) cultivars, interspecific hybrids, and wild-collected accessions using RADseq. PLOS ONE 19(7): e0307326. https://doi.org/10.1371/journal.pone.0307326 (opens in a new tab)

Nowicki M, Houston LC, Boggess SL, Aiello AS, et al. (2020) Species diversity and phylogeography of Cornus kousa (Asian dogwood) captured by genomic and genic microsatellites. Ecology and Evolution 10(15): 8299–8312. https://doi.org/10.1002/ece3.6537 (opens in a new tab)

Royal Botanic Gardens, Kew (2026) Cornus kousa Bürger ex Hance. Plants of the World Online. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30115668-2 (opens in a new tab)

Xiang Q-Y, Boufford DE (2005) Cornus. In: Wu ZY, Raven PH, Hong DY (eds) Flora of China, Vol. 14. Science Press, Beijing & Missouri Botanical Garden Press, St. Louis, pp. 206–221. https://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=108042 (opens in a new tab)