'Columella'

HYBRID CULTIVAR

‘Plantyn’ self- or openly-pollinated

ORIGIN

Dorschkamp, Netherlands; released 1987.

DESCRIPTION

‘Columella’ has a most distinctive fastigiate, monopodial structure, although the crown eventually broadens with age. The peculiarly twisted leaves are in asymmetric clusters on short branchlets, often encircling them and remaining thus well into winter, a trait inherited from its Exeter Elm ancestor. ‘Columella’ readily defoliates in drought, a trait inherited from its Himalayan elm ancestor. Trees in the Netherlands >25 years old are now collapsing because of graft incompata-bility with their wych elm rootstocks. However, all trees post-2012 have allegedly been raised on their own roots. One dozen trees planted near the sea in Portsmouth in 2003 all died, probably because of salt intolerance. Where planted as urban street trees, the cultivar appears to have been very successful in the UK.

PERFORMANCE

Stability

Resistance to exposure

Resemblance to native elm

Suitability for street planting

Rate of growth

Tolerance of waterlogging

Tolerance of drought