A vigorous shrub of garden origin, intermediate in features between its parents. Mature bark rougher than Corylus avellana; twigs darker red-brown with conspicuous pale lenticels. Leaves narrower, elliptic, more closely and sharply serrated, glabrescent, slighlty lobulate; nuts with short husks edged with spiny points with spiny or glandular bristles over the surface. (Rehder 1926).
USDA Hardiness Zone 6-7
RHS Hardiness Rating H5
Corylus × spinescens was described by Alfred Rehder in 1926 from a plant at the Arnold Arboretum in Massachusetts which had been received 15 years earlier as C. ferox var. tibetica from Maurice de Vilmorin’s nursery in France. Its leaves were slightly smaller, broader and hairier than expected, with less elongated marginal teeth but with slight lobes around the shoulders, and when it first produced nuts in 1925 the husks were more like those of C. avellana, but fringed and surfaced with a few of the spines which make the fruit of C. ferox so memorable; Rehder concluded that it was an accidental hybrid with C. avellana (Rehder 1926).
Although Rehder felt that the foliage was handsomer than that of C. avellana (Rehder 1926), the hybrid has not found a place in gardens (or in hazelnut culture). The original plant has long gone – possibly because of hardiness issues in North American Climate Zone 6, possibly through succumbing to Eastern Filbert Blight – and the only other example which we have been able to trace is a shrub at the Sir Harold Hillier Gardens in England (19781653*X), which was 6 m tall in 2001 (Tree Register 2023).
When Rehder described this hybrid, C. ferox var. tibetica was generally understood as a species in its own right (C. tibetica Batalin). Rehder therefore treated his plant as a hybrid of avellana and tibetica, but if, as in this account, tibetica is understood as a variety of C. ferox, the name C. × spinescens would also cover hybrids between C. avellana and C. ferox var. ferox, were these to occur (J. David pers. comm.).