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Cornus unalaschkensis Ledeb.

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Hugh and Judy Johnson

Credits

Martin Deasy, Dan Crowley, Jack Aldridge & Răzvan Chişu (2026)

Recommended citation
Deasy, M., Crowley, D., Aldridge, J. & Chişu, R. (2026), 'Cornus unalaschkensis ' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/cornus/cornus-unalaschkensis/). Accessed 2026-07-17.

Family

  • Cornaceae

Genus

Common Names

  • Western Bunchberry
  • Western Cordilleran Bunchberry

Synonyms

  • Arctocrania unalaschkensis (Ledeb.) Nakai
  • Chamaepericlymenum unalaschkense (Ledeb.) Rydb.
  • Cornella unalaschkensis (Ledeb.) Rydb.
  • Swida unalaschkensis (Ledeb.) A.Heller

Glossary

hybrid
Plant originating from the cross-fertilisation of genetically distinct individuals (e.g. two species or two subspecies).
included
(botanical) Contained within another part or organ.
rhizome
Persistent horizontal subterranean stem bearing roots and shoots. rhizomatous Having or resembling a rhizome.
subspecies
(subsp.) Taxonomic rank for a group of organisms showing the principal characters of a species but with significant definable morphological differentiation. A subspecies occurs in populations that can occupy a distinct geographical range or habitat.
whorl
Arrangement of three or more organs (leaves flowers) around a central axis. whorled Arranged in a whorl.

Credits

Martin Deasy, Dan Crowley, Jack Aldridge & Răzvan Chişu (2026)

Recommended citation
Deasy, M., Crowley, D., Aldridge, J. & Chişu, R. (2026), 'Cornus unalaschkensis ' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/cornus/cornus-unalaschkensis/). Accessed 2026-07-17.

Cornus unalaschkensis

Cornus unalaschkensis in its ideal mossy forest-floor conditions (Wild Pacific Trail, Vancouver Island, British Columbia, Canada; 21 May 2015). Image Koen Camelbeke, Arboretum Wespelaar.

Rhizomatous herb or subshrub to 22 cm. Stems green, appressed-pubescent, nodes four to six, internodes longer towards top of plant, branched only at apical node. Leaves opposite, those at the basal nodes usually non-chlorophyllous, scalelike and caducous, those at the uppermost node larger, chlorophyllous, persistent, in whorl of six, 3.5–8 × 0.9–4 cm (if lower nodes with chlorophyllous leaves, then these are smaller), elliptic to ovate, upper surface green, appressed pubescent, lower surface pale green, sparsely pubescent with appressed, trichomes or glabrous, three secondary veins on each side of the midvein, margins entire, apex acuminate; petiole to ~0.3 cm long. Inflorescence a compound cyme, 20–40-flowered; bracts four, petal-like, two ovate, 2.1–3 × 1.2–1.3 cm, two suborbiculate, 1.7–1.9 × 1.3–1.6 cm, greenish-white to white, often tipped red to purple, apex acuminate. Flowers with petals to ~0.2 cm long. Fruit a drupe, red, 10–20 per infructescence, globose, 0.6–0.8 cm diameter, stone globose or subglobose, longitudinally grooved, apex slightly pointed. Flowering May to August, fruiting August to October. (Murrell & Poindexter 2015; Wahlsteen et al. 2020).

Distribution  Canada Alberta, British Columbia, Yukon Russia Magadan, Khabarovsk United States Alaska, California, Idaho, Oregon, Washington, Aleutian Is.

Habitat Maritime coniferous forests and heaths, moist or boggy broadleaf or coniferous forest or woodland from sea level to 3000 m asl.

USDA Hardiness Zone 6a

RHS Hardiness Rating H7

Conservation status Not evaluated (NE)

One of four or five closely-related herbaceous species in subgenus Arctocrania – the so-called ‘bunchberry complex’ – included in the present treatment on the strength of the woody perennial rhizome, though some may feel that this is stretching a point. Cornus unalaschkensis is distributed around the North Pacific rim, from California to Alaska, the Aleutians and the far east of Russia as far south as Khabarovsk, forming clonal colonies on moist or boggy woodland floors. It has in the past been treated as a hybrid of Cornus canadensis and C. suecica, but as an allotetraploid that bears fertile fruits it is now recognised as a species in its own right.

Cornus unalaschkensis is distinguished from C. canadensis and C. suecica by its purple-tipped (not uniformly cream or purple) petals, and by the penultimate whorl of leaves, which are green (not scale-like as in C. canadensis) and much smaller than those in the distalmost whorl (in C. suecica the two whorls are roughly similar) (Murrell & Poindexter 2015). The ranges of the species in subgen. Arctocrania overlap, intermediate forms occurring (Murrell 1994). Based on genetic and biogeographical findings, Sun, Zhou and Xiang (2025) propose to recognise two cryptic subspecies (not yet published), subsp. unalaschkensis and subsp. borealis – of probable conservation relevance, given ongoing habitat shrinkage, but without horticultural significance. Cultivation is as for C. canadensis – that is, cool, moist acidic soil, as far as possible approximating open woodland conditions.

Cornus unalaschkensis

Cornus unalaschkensis growing epiphytically, a habit made possible by the high humidity of the Pacific temperate rain forest. Here the rhizomes are functionally equivalent to the aerial roots of orchids. The reduced leaves at the internode below the terminal whorl are clearly seen here (Wild Pacific Trail, Vancouver Island, British Columbia, Canada; 21 May 2015). Image Koen Camelbeke, Arboretum Wespelaar.

Cornus unalaschkensis

Cornus unalaschkensis growing wild at Brandywine Falls Park, British Columbia, Canada (23 May 2015). Image Koen Camelbeke, Arboretum Wespelaar.

Cornus unalaschkensis

Cornus unalaschkensis forms clonal colonies in woodland (wild plant, Clackamas Co., Oregon, USA; 21 July 2017). Image Julian Sutton.

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