Celtis occidentalis - Hackberry

Celtis occidentalis, native to North America, nicknamed the Hackberry, is a cousin of the Provençal Hackberry but more hardy. This fast-growing tree forms one or several trunks that branch out quite low. Its irregular habit gives it a somewhat wild appearance, ideal for natural gardens. Its ovate, fairly small, medium-green leaves take on a beautiful yellow autumn colour. The discreet spring flowering gives way to small edible fruits in autumn. With age, the trunk becomes quite thick and its grey, very warty bark is undeniably charming. It is a very hardy plant, perfect for beginners, adapting to most soils.

Once classified in the Ulmaceae family, Celtis moved to the Cannabaceae family in the early 2000s, alongside Cannabis and the Hops used in beer production. The Celtis genus includes around 70 species, mostly tropical and subtropical, with only about 15 being hardy in temperate climates. Celtis occidentalis is native to the United States, where it grows from the Appalachians to the Rocky Mountains, and Canada, explaining its great cold resistance, down to -34°C! However, insufficiently woody young shoots may freeze, causing lateral buds to sprout, giving a zigzag appearance. In its native regions, the tree can become very imposing, up to 30 m or more in height, but in our regions, it generally limits itself to around 15 m, with a spread of about 8 m. Fast-growing in its youth, it slows down later. Its growth is highly influenced by its growing conditions. It grows to its maximum in deep, moist soil and sunny locations, it will be smaller in sandy, dry, or partially shaded soils. Its habit is very irregular, and its silhouette varies between specimens, being more or less pyramidal, conical, or even slightly cylindrical as it ages. While its somewhat wild appearance is not very distinctive, this tree is more easily identified by its leaves. They are small, ovate, 5 to 12 cm long, borne on a short petiole of approximately 2 cm. Their base is slightly asymmetrical (like that of the Elm or Ulmus, a typical representative of the Ulmaceae family, the original family of the Hackberry). Intense green on the upper surface, slightly paler underneath, the surface is rough to the touch, another distinguishing feature. Similarly, the bark is easily identifiable on older specimens, as it is very warty, forming thick, rough, corky ridges, giving the trunk a particularly creviced appearance. Its grey colour and roughness make it an ornamental feature, especially in winter. The tree tends to develop multiple trunks, further enhancing its wild appearance. In April-May, small yellowish flowers appear, clustered in the axils of emerging young leaves. These small inflorescences have no ornamental value, but they are honey-producing and thus useful to pollinators. The tree is self-fertile, so these flowers produce small globose fruits, 1 cm in diameter, initially orange-red, turning to a dark purple, almost black at maturity. They are edible, with a sweet taste and persist on the plant for a long time in winter. When autumn and the first frosts arrive, the foliage gradually turns yellow before falling.

Hackberry is an interesting tree for its autumn colours, original bark, and very natural appearance. It is also, and above all, a species capable of thriving in almost all conditions. Accepting neutral, acidic, or calcareous soils, moist or even wet, but tolerating dryness once well-rooted, it is truly an "all-terrain" plant. Pair it with other free-form plants. Cornus mas (European Cornel) will be a perfect companion with its tousled habit, beautiful early yellow, fragrant and nectar-rich flowering, producing decorative and also edible red fruits. Plant it in front of your tree and in the third layer, place at its feet botanical roses, such as the charming Rosa glauca with its bluish foliage, enhanced by bright pink flowers followed by red berries, as well as Snowberries with their highly decorative winter fruits.