There are possibly 9 different species in this group, but the main two are Shagbark Hickory (Carya ovata) and Shellbark Hickory (Carya laciniosa).
A deciduous Tree growing to 30 m (98ft) by 15 m (49ft) at a slow rate. It is hardy to zone 4. It is in leaf 10-Jun It is in flower in June, and the seeds ripen from Oct to November. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by Wind.The plant is self-fertile.
The nuts can be eaten raw or cooked and used in pies, cakes, bread etc. Sweet and delicious. The shell is normally thick and hard but in selected cultivars it can be thin. The seed ripens in late autumn and can be stored for up to 2 years in a cool cellar. The seed is up to 4cm long. The sap is sweet and it is tapped in spring and can be made into a syrup.
Prefers a deep moisture-retentive loam in a sunny sheltered position, requiring a good summer for best development. Succeeds in drier soils than most members of this genus. It is very ornamental but a slow-growing tree. It grows well in Britain, especially when young, and does well in Cornwall. The tree has a loose grey bark that comes away in broad flakes and gives the tree its common name. The hickory is occasionally cultivated for its edible seed, there are some named varieties.