Corylus americana Walt.

Corylus americana is the common hazel species across large parts of the eastern United States. In leaf it is hardly distinguishable from the equivalent European species, C. avellana; its male catkins, produced very early in spring, have shorter stalks (1–5 mm rather than 5–12 mm), and the nuts, ripening through the end of summer, are equally tasty but rather smaller (c. 12 mm rather than c. 18 mm). The husks of the American plant are more elaborate – indeed showy – being much lobed and ruffled and always longer than the nut itself.

These two species also differ subtly in their ecology: Corylus avellana – native to a region more species-depleted after the last Ice Age – is typically a more abundant plant, even a co-dominant one, and can become a 15 m tree. C. americana is slightly less of a woodland species, being usually absent from old-growth forest communities and characteristic of the ecotone from forest to prairie (in Nebraska in particular); it is quick to invade waste land and was one of the first bushes to colonise after the last glaciation (Nomad Seed Project 2019; USDA 2023). It is very much a shrub, seldom passing five metres in height and developing thickets of small stems from below ground level – rather than from the root-crown as is true for C. avellana. This suckering habit helps its resprout after forest fires, but its ecology is much less fire dependent than that of the other ‘American hazel’, C. cornuta, and severe fires can kill the shallow root-system (USDA 2023). It is able to grow in very low light levels inside woods, but fruits best in full sun (Nomad Seed Project 2019).

The nut’s smaller size meant that Corylus americana quickly lost out in popularity among European settlers to cultivars derived from the Old World hazels, although the latter are readily killed by Eastern Filbert Blight (EFB) to which C. americana, as the natural host species, is largely immune, suffering minor cankers at worst. Both species produce straight, flexible poles which have many uses in basketry and fencing, but in the American plant these poles are never of much length. Native Americans used a herbal broth made from the bark of Corylus americana to treat hives and fevers, and a poultice to help wounds and sores to heal (Plants for a Future 2023; Nomad Seed Project 2019).

The American hazel’s qualities do not lend it to garden use. Even its autumn colour, in a biome where so many trees excel, is variable and only sometimes includes good orange and red tints (Dirr 2009). In cultivation in Europe, it is the kind of plant which only botanic gardens are likely to grow: Dawyck Botanic Garden in southern Scotland has a 1981 accession from Ontario, and the Sir Harold Hillier Gardens in England has a 1998 accession from Maryland (Royal Botanic Garden Edinburgh 2023). More surprisingly, three bushes about four metres high were a feature of the Val de la Mare Arboretum on Jersey in 2013 (Tree Register 2023), though it has to be admitted that plantings such as this are very likely to be overlooked once the label drops off. This is a tough plant, and is successfully cultivated at the Linnaean Gardens of Uppsala University in Sweden (Royal Botanic Garden Edinburgh 2023).