Hackberry

About the Hackberry

The hackberry (Celtis occidentalis) is one of the most adaptable and underappreciated native trees in Middle Tennessee. While it lacks the showy flowers of dogwood or the brilliant fall color of blackgum, it is one of the most ecologically valuable and site-tolerant large shade trees available to Nashville homeowners – tolerating drought, flooding, compacted soil, alkaline soil, air pollution, and urban heat that would stress or kill many other species.

Hackberry is instantly recognized in winter by its distinctive corky, warty bark with irregular ridges and knobs, and in summer by the bumpy leaf galls left by psyllid insects (harmless to the tree). It grows naturally throughout Middle Tennessee on floodplain edges, limestone bluffs, and upland sites, and is one of the most common native trees in the Nashville area.

For Nashville homeowners with difficult sites – challenging soil, compaction, alkaline conditions, or hot exposed locations – hackberry is frequently the best available large native shade tree option.

Identification

• Bark: Gray to gray-brown, with distinctive corky warts and ridges – one of the most recognizable barks of any native tree. This feature alone makes hackberry easy to identify year-round.
• Leaves: Ovate, 2 to 5 inches long, with an asymmetrical base and toothed margins. Rough, sandpaper-like upper surface. Light green to yellow-green in fall.
• Fruit: Small, round drupes, ¼ to ½ inch, ripening from orange-red to dark purple in fall. Sweet and edible. Persists on the tree into winter, providing food for birds.
• Form: Broad, irregular crown with somewhat drooping outer branches. Often develops "witch's broom" clusters of twiggy growth (harmless) caused by mites and fungi.

Planting & Care in Nashville

Hackberry is one of the easiest native trees to establish and maintain in Nashville.

• Soil adaptability: Hackberry grows in virtually any soil type – clay, loam, sand, wet, dry, alkaline (limestone-derived), acidic, or compacted. This adaptability makes it exceptional for Nashville's varied soil conditions, including the alkaline clay soils common in many parts of Davidson County.
• Sun: Full sun to partial shade. Performs best and grows most rapidly in full sun.
• Drought tolerance: Once established, hackberry is highly drought-tolerant. It is an excellent choice for sites that receive little supplemental irrigation.
• Urban tolerance: One of the most pollution-tolerant native trees. Hackberry thrives in street-side plantings, parking lot islands, and other urban sites with reflected heat and compacted soil.
• Cosmetic issues: Hackberry regularly develops psyllid galls on leaves and witch's broom clusters on branches. Both are cosmetic and do not harm tree health. No treatment is needed.
• Pruning: Prune in late winter or early spring to remove dead wood and improve structure. Hackberry can develop included bark (bark trapped between co-dominant stems) – early structural pruning prevents future problems.

Wildlife Value & Nashville Relevance

Hackberry is among the most ecologically productive native trees in Middle Tennessee. Its contributions include:

• Lepidoptera host plant: Hackberry is the primary larval host plant for several butterfly species, including the hackberry emperor, tawny emperor, and American snout butterfly. These butterflies are dependent on hackberry for reproduction.
• Wildlife food: The persistent berries are consumed throughout fall and winter by dozens of bird species including American robins, cedar waxwings, mockingbirds, yellow-rumped warblers, and many others. Small mammals also consume the berries.
• Cavity habitat: Old hackberry trees develop cavities used by nesting birds and small mammals.

Hackberry is a common native tree across Nashville's parks and natural areas. On many sites where soil conditions are too difficult for oaks, maples, or other preferred shade trees, hackberry is the practical choice that will thrive where others struggle.