Corylus × vilmorinii Rehder

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Credits

Owen Johnson & Richard Moore (2023)

Recommended citation
Johnson, O. & Moore, R. (2023), 'Corylus × vilmorinii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/corylus/corylus-x-vilmorinii/). Accessed 2024-07-18.

Genus

Common Names

  • Chinese Trazel
  • Vilmorin's Hazel

Synonyms

Glossary

hybrid
Plant originating from the cross-fertilisation of genetically distinct individuals (e.g. two species or two subspecies).
nut
Dry indehiscent single-seeded fruit with woody outer wall.
pollen
Small grains that contain the male reproductive cells. Produced in the anther.
taxon
(pl. taxa) Group of organisms sharing the same taxonomic rank (family genus species infraspecific variety).

Credits

Owen Johnson & Richard Moore (2023)

Recommended citation
Johnson, O. & Moore, R. (2023), 'Corylus × vilmorinii' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/corylus/corylus-x-vilmorinii/). Accessed 2024-07-18.

A hybrid of garden origin. Large tree, sometimes spire-shaped in youth. Leaves slightly shorter than those of Corylus chinensis, less deeply or unequally cordate at the base and more abruptly acuminate, with sharper marginal serrations. Male catkins exceptionally long (to 15 cm). Nut larger and thinner-shelled than C. chinensis, the involucre scarcely constricted above the nut and with very deep and irregular dentate lobing at the top, often with one division reaching almost to the base of the husk. (Rehder 1926; Taylor & Kirkham 2005).

USDA Hardiness Zone 6

RHS Hardiness Rating H6

A hazel at the Arnold Arboretum in Massachusetts, received from Maurice de Vilmorin’s nursery in France in 1911 as a seedling from Vilmorin’s plant of Corylus chinensis, had shorter and broader leaves than expected, and when it began the fruit the husk did not form a smooth tube constricted above the nut, as in that species. This plant was described by Alfred Rehder in 1926 as an accidental hybrid with C. avellana, the likeliest species to have pollinated Vilmorin’s C. chinensis. The bracts do show intermediate features, but in cultivation this taxon tends to make trees almost as vigorous and straight as C. chinensis itself, leading some authorities (e.g. Govaerts 2003) to treat it as an Unplaced Name, though it is hard to come up with a better candidate for the pollen parent. Very similar hybrids have accidentally arisen in cultivation numerous times, making it even less likely than another, scarcer hazel species could each time have been the pollinator.

The original tree proved hardy in North American Climate Zone 6 and still grows at the Arnold Arboretum (7549*A), having so far withstood Eastern Filbert Blight, with another accession here from 2016 (Arnold Arboretum 2023). At the Royal Botanic Gardens, Kew, England, a tree also identified as Corylus × vilmorinii was received from Vilmorin in 1924 (Bean 1981), so must have been an independent cross. This has long gone, and a second hybrid growing at Kew in 2005 was of unknown origin, having wrongly been catalogued as a scion raised from a cutting from a genuine old C. chinensis which still grows at Kew (Taylor & Kirkham 2005). Another English tree, at Hergest Croft in Herefordshire, was catalogued – and presumably purchased – as C. chinensis and grew to 20 m on a straight stem. It was identified as a hybrid by Roy Lancaster in 1983; the trunk broke two metres above the ground some time after 1995, but by 2013 the tree was recovering well (Clarke 1988; Tree Register 2023; R. Griffiths pers. comm. to RM). The Sir Harold Hillier Gardens have a younger plant, accessioned in 2007 (Royal Botanic Garden Edinburgh 2023).

At Oregon State University in the 1990s, Veli Erdogan and Shawn Mehlenbacher found that plants of Corylus chinensis artificially pollinated by C. avellana (but not vice-versa) produced the most vigorous offspring of all of their many hazel hybrids (Erdogan & Mehlenbacher 2000). C. × vilmorinii may therefore prove to be particularly useful as a mass-produced non-suckering rootstock for commercial nut trees (Molnar 2011). As a garden plant, ‘pure’ C. chinensis is presumably preferable, but the particularly long and profuse catkins of the hybrid are an attractive feature (Taylor & Kirkham 2005). Scions of yet another accidental cross which arose at Ness Botanic Gardens in the UK from seed of C. chinensis are now available from Pan-Global Plants (Pan-Global Plants 2023).