Sugarberry & Hackberry trees: Quirky, corky growth on bark makes them unique

I often write about how flowers aren’t the only ornamental characteristic by which we should judge the aesthetic value of plants. Sure, pretty blooms are nice, but plants do other things as well. There are, of course, many plants whose primary attribute is their attractive fruit, or their colorful fall foliage. Sometimes even more subtle attributes, such as bark color or texture, may be the thing that first catches your eye when observing a plant.

Perhaps that’s the case with sugarberry, Celtis laevigata, or it’s close cousin hackberry, Celtis occidentalis. Both are known for the corky growth that develops on their trunks and branches. Initially these corky growths may appear as individual bumps or warts, but they increase in size as the trees age, often creating deeply furrowed ridges along the trunk. This may not be pretty, in the classic sense, but it is certainly notable, and if trunks are your thing, this very well may float your boat.

The above photo gives an idea of how high Sugarberry and Hackberry trees can grow under ideal conditions. The unusual corky bark growths provide visual interest for both trees. Left photo: R. Murphy, CC BY-SA 3.0. Right photo: K. Woods, CC BY-NC-SA 2.0

Left: The fall colors of the Hackberry. Both the Sugarberry and Hackberry trees are deciduous native trees. Photo: J. Robbins, CC BY-NC-ND 4.0. Right: The broad shape of the Sugarberry provides shade for sidewalks, parking lots, and gardens. Photo: J. Robbins, CC-BY-NC-ND 4.0.

Beyond this somewhat unusual physical trait, both sugarberry and hackberry are tall deciduous trees that cast quite a bit of shade. They are often used as street trees in urban areas for this reason, lining sidewalks and parking lots. They can be a bit messy, however, as they produce many small red berries that can get stepped on and smushed. The berries do offer another small bit of ornamental value, but more than this, they are valuable as a food source for many birds and small mammals who feed on them. Sugarberry and hackberry both also serve as host or food source for a large number of butterfly species, including the Hackberry Emperor, American Snout, Morning Cloak, Tawny Emperor, and Question Mark butterfly. They are pretty large for the average home landscape – hackberry grows 40-60’ tall, and sugarberry 50-70’. But if you are a native plant enthusiast who also values pollinators, either of these trees would be a good thematic fit in your landscape.

Both trees are related to elm, though both seem to have resistance to the problematic Dutch elm disease, which has decimated the American elm population. It is also part of the Hemp (Cannabaceae) family, and though it doesn’t seem to share any of the intoxicating effects of other relatives, perhaps that relationship is why this plant was used by some Native Americans for medicinal purposes. A concoction made from the bark was used to treat sore throats and other ailments, and parts of this tree have also been used historically to make food, fuel, and tools. In more modern times, the wood from hackberry is used to make furniture and baskets.

Although we often think of natives as relatively pest free, both hackberry and sugarberry have a number of minor pest issues. Aphids love tender new growth, and the excretions of their feeding often lead to black sooty mold. They are also prone to powdery mildew, leaf spot, and an unsightly but mostly harmless condition called hackberry nipple gall, which causes a bumpy distortion to infected leaves.  

Matthew Stevens is the horticulture extension agent for North Carolina Cooperative Extension’s Pitt County Center. If you have any questions about this article or other aspects of your home gardening, please contact the Pitt County Master Gardener Infoline at 252-902-1705.