Columella Elm (Ulmus 'Columella')

'Columella' is a European elm cultivar developed by the Dutch elm breeding program at Wageningen. It is distinguished by a strongly columnar (narrowly upright) form that suits constrained urban planting sites where conventional spreading elms would not fit.

Origin

'Columella' was developed by Hans Heybroek at the Dorschkamp Institute (now part of Wageningen University & Research) in the Netherlands as part of the long-running Dutch resistance breeding program initiated in the 1920s after the original Ophiostoma ulmi outbreak. The cultivar derives from a complex hybrid background incorporating European field elm (Ulmus minor) and Asian resistant species.

Commercial release came in 1989. Like other Dutch breeding releases, 'Columella' was developed with European urban applications in mind, but it has also been adopted to a lesser extent in North America.

Identification

  • Form: Distinctly narrow columnar — strongly upright with a tight branching habit
  • Mature size: 40–50 feet tall, only 10–15 foot crown spread
  • Leaves: Smaller than American elm — 2–3 inches, double-serrated, asymmetric base, dark green
  • Bark: Gray-brown, fissured with age
  • Growth rate: Moderate

Hardiness and adaptability

  • USDA hardiness zones: 5–8
  • Site preferences: Adaptable; tolerates urban conditions and a range of soil types
  • Stress tolerance: Drought-tolerant once established

Dutch Elm Disease resistance

'Columella' demonstrates high DED resistance. The cultivar has performed strongly in European field trials over more than three decades. Resistance is derived from the cultivar's hybrid Asian-European parentage.

The Dutch breeding program reports survival rates above 80% in inoculation-pressure trials, comparable to the top American hybrids (Heybroek 1993).

Landscape uses

  • Narrow urban right-of-way street trees where spreading cultivars cannot fit
  • Allée plantings where a tight columnar silhouette is aesthetically desired
  • Screening and privacy plantings
  • Specimen plantings in formal landscape designs

Limitations

  • Columnar form is distinctly different from classic American elm; not suitable for plantings seeking the spreading vase aesthetic
  • Less widely available in North America than American releases
  • Smaller mature size limits canopy contribution per tree
  • Performance in cold-region zones below 5 is unreliable

Similar cultivars

  • 'Wanoux' (Vada) — another European narrow-form selection
  • 'Sapporo Autumn Gold' — narrower Japanese elm cultivar
  • 'Jefferson' — American elm with somewhat narrower-than-classic form

Related pages

References

  • Heybroek, H. M. (1993). "The Dutch elm breeding program." In Dutch Elm Disease Research: Cellular and Molecular Approaches (pp. 16–25). Springer.
  • Solla, A., et al. (2005). "Genetic variation and heritability estimates of Ulmus minor and Ulmus pumila hybrids for budburst, growth and tolerance to Ophiostoma novo-ulmi." Investigación Agraria: Sistemas y Recursos Forestales, 14(1), 122–130.
  • Mittempergher, L., & Santini, A. (2004). "The history of elm breeding." Investigación Agraria: Sistemas y Recursos Forestales, 13(1), 161–177.