Hydrangea peruviana
Ecuadorian sprawling hydrangea
Synonyms
- Cornidia peruviana ( )
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Introduction
Ecuadorian sprawling hydrangea is perhaps the greatest taxonomic irony in Section Cornidia. For decades, Hydrangea peruviana was treated as one of the most widespread climbing hydrangeas in the Neotropics, with a range stretching across much of Central and South America. Type-anchored revision has instead shown that true H. peruviana is a rare Ecuadorian endemic, known from remarkably few modern collections. A name once used as a taxonomic catch-all now belongs to one of the narrower and more threatened species in the complex (Samain et al. 2021).
It is a substantial functionally dioecious root-climber reaching about 30 m and developing stems up to roughly 20 cm thick. The leaves are leathery and very slightly spoon-shaped, elliptic to somewhat obovate, with reddish-brown stellate pubescence, acute to acuminate tips, and serrate to weakly dentate margins. Numerous acarodomatia occur not only where the principal veins meet the midrib but also at some secondary-vein junctions, producing a much richer pattern of mite-associated cavities than in its sister species H. panamensis (Samain et al. 2021).
Its flowering biology is still incompletely known. Enlarged marginal flowers are consistently present in the available material, and flowering shoots carry dense reddish stellate hairs. Yet the modern revision encountered only functionally female individuals; no male plant was known from the specimens examined. That does not imply a female-only species, but it emphasizes how incomplete sampling remains even for the nominal species around which the old complex was built (Samain et al. 2021).
The species' name also preserves a fascinating piece of botanical geography. The original material was labelled from “Peru near Guayaquil,” even though Guayaquil lies in modern Ecuador. When the collection was made in the late eighteenth century, however, the political-geographic term Peru could encompass a much larger region associated with the former Viceroyalty of Peru. Historical scholarship further suggests that collections from the Ecuadorian region attributed to Ruiz and Pavón were in fact made by their collaborator Juan José Tafalla. Hydrangea peruviana is therefore neither a modern Peruvian species nor simply a botanical naming error; the epithet records the administrative and collecting history of an earlier South America (Samain et al. 2021).
The molecular result is exceptionally satisfying. The single sampled true H. peruviana is sister to strongly monophyletic H. panamensis within Clade K. These two species are genuinely close relatives, yet they are separated by clear differences in leaf shape, acarodomatia, geography, elevation, and ecology. Meanwhile, most of the other plants historically called H. peruviana occur elsewhere in the Cornidia tree. The old broad species was therefore not merely morphologically variable; it combined multiple evolutionary lineages (Granados Mendoza et al. 2021).
The secure synonym Cornidia peruviana (Moric. ex Ser.) Small represents the same nomenclatural type. Tree TSAR restricts H. peruviana to the Ecuadorian lineage rather than reproducing the broad backbone concept.
Horticultural and Agricultural Uses
The horticultural history associated with the name H. peruviana is much less secure than it once appeared. Plants under that name have occasionally circulated in mild gardens, but the taxonomic revision means that older accessions lacking wild provenance cannot automatically be assumed to represent true Ecuadorian H. peruviana. Trees and Shrubs Online explicitly recommends re-identifying cultivated material formerly labelled H. peruviana or H. oerstedii (Sutton 2025).
A putative hybrid distributed in southern England as H. peruviana × serratifolia is horticulturally impressive and significantly hardier than most tropical Cornidia, but its parentage has never been conclusively verified. It therefore provides evidence of the horticultural possibilities of the group, not proof that true H. peruviana itself is commonly cultivated (Sutton 2025).
Authentic Ecuadorian material would have great breeding and conservation interest. Pink to reddish-purple pigmentation in the complex, evergreen climbing architecture, and potential compatibility with temperate Cornidia make these plants attractive experimental breeding material, but provenance verification must come before parentage claims.
Conservation Concerns
True H. peruviana is rare. Samain et al. located only six collections made since 1980 in addition to the historical type material. During modern field work they found it flowering roughly 30 m above the ground in primary mountain cloud forest; persistent cloud and the height of the canopy made the plants extremely difficult to detect, offering at least a partial explanation for their sparse collection history (Samain et al. 2021).
The specialist revision assessed the species as Endangered, with an extent of occurrence of about 13,515 km², an area of occupancy of roughly 20 km², fewer than five known locations, and severe ongoing habitat destruction and fragmentation (Samain et al. 2021).
The absence of known males from modern collections adds a reproductive uncertainty that deserves focused field study. Surveys should document the sex of every located individual, population spacing, host-tree dependence, and whether populations can sustain seed production.
The contrast with current databases is stark. Plants of the World Online still presents H. peruviana as native from Costa Rica to Bolivia and northwestern Venezuela and accepts two varieties, while synonymizing several specialist-recognized species beneath the typical variety. Readers using those records for range mapping or conservation would therefore obtain a radically different picture from the type-anchored 2021 revision (Royal Botanic Gardens, Kew 2026).
Additional Information
- iNaturalist — Hydrangea peruviana (opens in a new tab): — the current iNaturalist taxon page still reflects a broad species concept and even displays a broad conservation status inconsistent with the narrowly revised Ecuadorian species, so its distributional information requires particular caution.
References and Further Reading
Granados Mendoza C, Martínez Salas EM, Goetghebeur P, Wanke S, Samain M-S (2021) Molecular phylogeny, character evolution, and biogeography of Hydrangea section Cornidia, Hydrangeaceae. Frontiers in Plant Science 12: 661522. https://doi.org/10.3389/fpls.2021.661522 (opens in a new tab)
McClintock E (1957) A monograph of the genus Hydrangea. Proceedings of the California Academy of Sciences, Fourth Series 29(5): 147–256. https://www.biodiversitylibrary.org/part/51707 (opens in a new tab) https://doi.org/10.5281/zenodo.15905786 (opens in a new tab)
Samain M-S, Granados Mendoza C, Martínez Salas EM (2021) On Hydrangea peruviana, an endangered species from Ecuador, and Hydrangea oerstedii, very common in Costa Rica and Panama, and seven threatened Central and South American hydrangeas, which have been confounded with these. PhytoKeys 171: 91–153. https://doi.org/10.3897/phytokeys.171.56351 (opens in a new tab)
Sutton J (2025) Hydrangea species of Section Cornidia. Trees and Shrubs Online. International Dendrology Society. https://www.treesandshrubsonline.org/articles/hydrangea/hydrangea-species-of-section-cornidia/ (opens in a new tab)