Many trees can easily be identified by their bark in the winter. One of these is our Midwest native Hackberry (Celtis occidentalis). “Hackberry” is a corruption of the Scottish “Hagberry,” which the English refer to as the Bird Cherry. The fruit of Hackberry is dark purple to almost black, which could lead one to confuse it with another Midwest native tree, the black cherry (Prunus serotina). The fruit of hackberry is fleshy, very unusual for a member of the Elm family (Ulmaceae), which typically has dry, winged fruit. Turkeys, pheasants, quail, and other birds find the pea-sized stony fruit highly palatable. Native Americans also made use of the fruit and seed, pounding it into a flour which was used in flavoring meats.
Hackberry, preferring rich bottomland soils, is a tree which is widely scattered over the northern United States. In Wisconsin it covers the entire state, with the exception of the northern tier of counties. Hackberry is found throughout Ozaukee County, where I live, but never in sufficient quantities to dominate a wooded area. It will tolerate periodic flooding, but not soil with a high water table or that which is constantly wet. However, it is not adverse to poor, dry soil either. The tree grows rapidly to a height of over 60 feet, which may make it too big for many residential sites, but useful in parks and other large areas. Resistant to salt and heat, and easily transplanted from nurseries, it has also found use as an urban street tree.
Perhaps the most interesting characteristic of hackberry is its bark, which on intermediate sized branches looks warty or appears to have pebbles attached. As the trunk matures it becomes blocky and takes on the appearance of small chips. Mature at 100 years of age, it commonly survives 200 years in wooded areas.
The wood of hackberry is tough but flexible, producing a nice grain which resembles ash. It splits straight down a branch and appears clean and white. Because of its free splitting nature, it was used to make floors in pioneer cabins, and barrel hoops. Daniel Harmon Brush (1813-1890) said in his book Growing up with Southern Illinois, “The floors of the cabins were made of puncheons split as thin as desired from hunks of the hackberry tree, a very free-splitting wood of firm and beautiful grain, and white in color. The logs were cut in convenient lengths and split into pieces as wide as possible, which were straightened on the edges and hewed on the surface to be laid uppermost to a thickness that would make the floor when laid as even as possible; all of which being carefully and neatly done, made a floor nice enough to content any sensible housewife who could not afford carpets. It was satisfactory to my good mother for all the years of her early experience in our first home in the new country.” Currently, hackberry wood has few uses, being employed only in inexpensive furniture, crates, and boxes.
Unfortunately, hackberry has a couple of aesthetically debilitating problems. Witches’ brooms, caused by mites and fungi, are common on young twigs. These “brooms” result in a dense, twiggy cluster on the branches. In addition, the leaves, almost without exception, are crippled on the lower side by a bullet-shaped growth called nipple gall. The cultivar ‘Prairie Pride’ is reported to have resistance to this malady. While neither problem is fatal, both severely limit the tree’s aesthetic value.
Other cultivars selected for urban use are ‘Chicagoland,’ which has a strong central leader and is narrower than the species, ‘Magnifica,’ which has a broad oval to vase shape, Prairie Sentinel™, a narrow columnar form, and Ultra™, which has a round form and blue-green foliage. Hackberry is an important tree in the Eastern deciduous forest, and is being used more frequently as a street tree. Though it is not one of my favorite trees for a highly manicured landscape, I would not hesitate to use it for naturalization.
The Cottage Gardener 