Celtis is genus of around 70 species of deciduous trees and shrubs.
C.australis grows to around 60 feet although it is not fully hardy in Britain. Another species, C.oxxidentalis is taller at around 80 feet, it has a corky bark and produces berries coloured either orange-red or dark-purple.
These should be planted in trays or boxes either in a greenhouse or outdoors if you are planting in the spring. They require pruning in November and December during their early development. You can propagate them in February and March by sowing their seeds in the greenhouse.