Celtis occidentalis Seeds | Common Hackberry
LATIN NAME: Celtis occidentalis
COMMON NAME: Common Hackberry, Northern Hackberry
Plant Profile
The hackberry’s bark is its signature: smooth grey young bark breaking into corky ridges and warty excrescences that give mature trunks a knobbled, almost barnacled look. The leaves are oval with a lopsided base, three main veins fanning from the petiole as in the elms it once sat beside, and margins coarsely toothed; they turn a soft yellow in autumn. Flowers are insignificant, greenish and wind-pollinated, appearing with the foliage in spring.
The fruit does the tree’s public relations. Small round drupes ripen from orange-red to dark purple, hang on thin stalks, and persist well into winter, feeding robins, cedar waxwings and other birds long after the frost. Inside each is a single bony stone. Mature trees reach fifteen to twenty metres with a rounded, arching crown, and their wood, though pale and unglamorous, splits readily enough to serve for rough fencing and cheap furniture.
The leaves are the caterpillar food of the hackberry emperor (Asterocampa celtis) and the tawny emperor, two butterflies whose adults famously land on people to sip sweat in midwestern summers. A planting of hackberry is therefore a butterfly planting in a way few street trees are. Wintering birds, in turn, depend on the persistent drupes, making the tree a keystone of wildlife hedgerows across its range.
Botanically the genus is wide, with relatives on every continent from the Mediterranean nettle tree to the Chinese hackberries grown as street trees in Asian cities, and molecular studies shuffled the family twice in a generation — first into its own Celtidaceae, then into the hemp family proper. The hackberry keeps a respectable distance from its psychoactive cousins, containing nothing of interest beyond sugar and a stony seed, and its similarity to elms turns out to be convergence rather than kinship, the two lineages having arrived at the same three-veined leaf by separate routes.
Science & Biotechnology
The galls are more than a curiosity. Pachypsylla psyllids induce their striking outgrowths by hijacking the leaf’s own growth machinery, and the hackberry system has become a model for studying how gall insects reprogramme plant development — questions with real biotechnological reach, from wound-healing to engineered tissue growth. Researchers have also screened hackberry and its relatives for phytoremediation of urban soils, drawing on the species’ notorious tolerance of salt, drought and compacted ground.
Uses & Benefits
Indigenous peoples of the plains and woodlands gathered the sweet fruit, eating it fresh and pounding the dried berries with parched seeds and animal fat into a travelling food; the stones were also cracked for the kernel inside. Settlers learned the habit, and in lean country the hackberry earned its reputation as a poor man’s date. The flavour is thin-sweet and figgy, with a crunch of stone that everyone learns to spit with style.
As a cultivated tree it is the ultimate tough-site choice: salt spray, drought, alkaline soil, air pollution and parking-lot heat all fail to slow it, which is why city foresters keep returning to it where elms and maples decline. Landscape designers value the arching, slightly pendulous branch tips that give old hackberries a windswept elegance. Woodworkers turn the pale yellow timber into bowls and tool handles, though supply is scattered and local.
Growing from Seed
The bony stones need patience: give them a warm moist period followed by a winter of cold stratification in sand, then sow one to two centimetres deep in nursery beds of loamy compost. Emergence is irregular within the tray, so plan on leaving beds undisturbed and pricking out seedlings as they come. Guard against mice, which relish the stones as much as birds do.
Line out seedlings when they stand about thirty centimetres, and move them to final positions at one to two metres in height, spacing eight to ten metres for boulevards. Once roots take hold the tree needs little beyond an occasional mulch and a formative prune to a single leader; dead wood and crossing limbs can be removed in late winter. The nipplegall psyllid disfigures foliage cosmetically but rarely harms the tree, and witches’ brooms — dense tangles of shoots caused by mites and fungus together — can be pruned out where they offend. Leafrollers and lace bugs appear in some seasons; healthy trees outgrow both.
Our Take
If your soil defeats prettier trees, plant a hackberry and watch it succeed in spite of everything. Its Old World cousins make good comparisons: Celtis sinensis in Chinese gardens, the regional Celtis kunmingensis of Yunnan, and the paper-tree relative Pteroceltis tatarinowii of northern China. Leave the fruiting branches for the birds each winter; they will repay you by planting the next generation where you would never think to.
Related Reading
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