Synonyms
- Adamia × versicolor
- Dichroa × versicolor ()
- × Didrangea versicolor ()
On this page
Introduction
Sapphire hydrangea, Hydrangea × versicolor (Fortune) J.M.H.Shaw, is an intersectional hybrid combining the bluebead lineage of Hydrangea febrifuga with the bigleaf-hydrangea lineage of H. macrophylla. Under the modern classification its parentage bridges Section Dichroa and Section Macrophyllae. It is simultaneously one of the oldest named unusual hydrangeas in Western horticulture and one of the most taxonomically complicated.
Hybrid formula: Hydrangea febrifuga × Hydrangea macrophylla
Robert Fortune encountered the plant in Hong Kong during the 1840s, and it was described in 1846 as Adamia × versicolor. Later authors transferred it to Dichroa and eventually placed hybrids between the traditional genera Dichroa and Hydrangea in the nothogenus × Didrangea. Once Dichroa was recognized as part of broad Hydrangea, those generic boundaries became unnecessary, and Shaw made the modern combination Hydrangea × versicolor in 2021. Its synonymy therefore records changing ideas about generic boundaries rather than different biological entities: Adamia × versicolor, Dichroa × versicolor, and × Didrangea versicolor are all based on the same name.
The hybrid combines strikingly different parental syndromes. H. febrifuga is an evergreen or semi-evergreen bluebead hydrangea lacking enlarged sterile marginal flowers and producing fleshy blue-purple berries. H. macrophylla is the large-leaved Japanese hydrangea whose ordinary wild inflorescences carry enlarged marginal flowers and whose fruit is a dry capsule. Plants assigned to H. × versicolor commonly combine large macrophylla-like leaves with all-fertile or nearly all-fertile inflorescences and blue-to-pink fertile flowers reminiscent of Section Dichroa. Some clones can potentially produce purple berry-like fruits, while many cultivated plants are sterile or produce only poor, capsule-like fruits.
The hybrid origin is supported by molecular evidence. Microsatellite analysis found Dichroa versicolor accessions clustering with experimentally confirmed hybrids between H. macrophylla and bluebead hydrangeas, supporting the long-suspected parentage rather than an independent species origin. Experimental work also demonstrated that these lineages can be crossed without embryo rescue and can produce fertile hybrid offspring.
The biological concept is nevertheless more complicated than a single historical cross. Plants now called H. × versicolor appear to encompass at least three sources: old Hong Kong material, hybrids produced accidentally or deliberately in Western cultivation, and additional Asian plants interpreted as members of the same hybrid combination. The original Hong Kong plants may themselves have been cultivated or naturalized there, and the precise place at which the ancestral hybridization occurred is uncertain.
Nor is every modern bluebead × bigleaf hybrid necessarily genetically identical to the historical nothospecies. One especially important breeding accession, GUIZ 48, was long identified as Dichroa febrifuga but is now considered a strong candidate for H. daimingshanensis. Crosses involving that accession therefore demonstrate compatibility between Section Dichroa and Macrophyllae but may not represent H. febrifuga × H. macrophylla in the strictest possible sense.
The most useful interpretation is consequently that H. × versicolor denotes the historically established H. febrifuga × H. macrophylla nothospecies, while superficially similar hybrids involving other Section-Dichroa parents require independent documentation rather than automatic assignment to the same formula.
Horticultural and Agricultural Uses
Sapphire hydrangea has considerably greater horticultural importance than the other named intersectional hybrids in this group. It can form an evergreen shrub 2–3 m tall in mild climates, with large leaves and unusual blue, violet, pinkish, or intermediate fertile flowers. Several garden selections have circulated, including ‘Cambridge Blue’, ‘Pink Candy’, and ‘Summer Skies’.
Its principal breeding value lies in combining characteristics rarely found together in conventional garden hydrangeas. Section Dichroa contributes evergreen foliage, intensely pigmented fertile flowers that can remain blue under conditions where H. macrophylla would turn pink, and potentially persistent blue fruits. Section Macrophyllae contributes large leaves, garden adaptability, and the enormous cultivated gene pool of bigleaf hydrangea.
USDA breeding experiments confirmed that even crosses across substantial ploidy differences can yield viable hybrids. A hexaploid bluebead accession was successfully crossed with diploid and triploid H. macrophylla cultivars, and some resulting hybrids retained fertility. This demonstrates that the cross is not merely a horticultural curiosity but a potential genetic bridge for further breeding.
The group remains tender compared with ordinary H. macrophylla, generally best suited to mild climates or protected cultivation. Trees and Shrubs Online estimates approximately USDA Zones 9–10 and RHS H3 for representative material.
Conservation Concerns
Hydrangea × versicolor is not appropriately viewed as an independently threatened wild species. Its historical Hong Kong populations include cultivated and apparently naturalized material, and the original geographic origin of the hybrid is uncertain.
Its principal conservation value lies in two areas. First, historic cultivated clones preserve a remarkable nineteenth-century example of intersectional hybridization. Second, wild genetic diversity in H. febrifuga, H. macrophylla, and their sectional relatives represents a much larger reservoir of traits than the small number of clones historically carried through horticulture.
Accurate identification is particularly important because genuine H. febrifuga has often been confused in gardens with H. × versicolor, while other bluebead species are increasingly entering cultivation under still more inconsistent names. Preservation of vouchers and provenance is therefore as important here as maintenance of the plants themselves.
Additional Information
References and Further Reading
Hunt DR (1981) Dichroa versicolor. Curtis's Botanical Magazine 183(3): 107–110. https://biotanz.landcareresearch.co.nz/references/366c196f-015c-40a2-818b-f535c67ee4a6 (opens in a new tab)
Lindley J (1846) New plants, etc., from the Society's garden. 45. Adamia versicolor. Journal of the Horticultural Society of London 1: 298. https://archive.org/details/journalofhorticusl01hort (opens in a new tab)
Rinehart TA, Scheffler BE, Reed SM (2010) Ploidy variation and genetic diversity in Dichroa. HortScience 45(2): 208–213. https://doi.org/10.21273/HORTSCI.45.2.208 (opens in a new tab)
Samain MS (2021) Hydrangea grows bigger. The Plant Review 3(4): 52–56.
Shaw JMH (2014) Hybrids between Dichroa and Hydrangea. The Plantsman, New Series 13(1): 16–21. https://www.rhs.org.uk/about-us/pdfs/publications/the-plant-review/general-pdfs/index-for-2014 (opens in a new tab)