Two species of Elm can be found on the Isles of Scilly; Cornish Elm (Ulmus minor ‘stricta’) and Dutch Elm (Ulmus x hollandica) (the latter being a hybrid between Wych Elm and Smooth-leaved Elm).  They can be found in mature hedgerows, or as shelterbelts across all the islands.

The trees can be identified in early March when they produce an abundance of small purple and white flowers before coming into leaf, utilising the wind to cross pollinate.  The pollinated flowers develop later in the year into samarae, small-winged fruits often known as ‘helicopters.’  However, the fruit are rarely fertile, instead the trees readily propagate from root suckers.

The identification of Cornish Elm can be separated from Dutch Elm with practice! Cornish Elm has glossy, dark green upper leaves which are smooth to touch and curve slightly upwards from their mid-ribs, in contrast to the rough texture of the upper surface of the flattened leaves of Dutch Elm.  The trunk of Cornish Elm is relatively straight and the crown has a conical shape.  The trunk of Dutch Elm is described as tortuous and has a mushroom-shaped crown. 

Both species are important larval and food plants for Comma Butterfly (Polygonia c-album), a rare species on Scilly, whilst mature trees provide nest sites for the UK conservation status Amber-listed Stock Dove (Columba oenas).