Hackberry Celtis occidentalis

Also known as the nettle tree due to the shape of its leaves, the hackberry is most easily recognised by its grey warty bark. Often afflicted by minor diseases it remains one of the most common trees in its native habitat of North America.

The common hackberry was introduced to Britain as long ago as 1636 but remains a rarity that is usually found only in botanical collections. This is not due to the climate as Celtis occidentalis is quite hardy and adapts readily to many different conditions, so must have been overlooked for other reasons.

Aesthetically speaking there are certainly more attractive trees and the hackberry is probably most easily recognised by its rough, warty bark. A pale grey colour, the lumps and bumps on the bark become more pronounced as time goes by until it is little more than a collection of calluses, knobs and ridges.

It is also prone to damage from insects and fungi. This includes growths called galls that appear on the underside of leaves after insects have fed on them, and mistletoe, which can kill the hackberry over time. Perhaps the tree's most common affliction though is witch's broom, a condition caused by mites and mildew, whereby a mass of shoots appear from one place on a branch giving the appearance of a witch's broom.

The hackberry does however have some redeeming features. Its tolerance for shade, drought and a range of soils makes it suitable for urban life and it has been planted extensively in Texas and other cities along streets and in parks. Even without this urbanisation it is one of the more common trees in the North America and can be found from Quebec in Canada down to Georgia in the south of the United States.