Elm - Uses of Elms in Landscaping

Uses of Elms in Landscaping

From the 18th century to the early 20th century, elms were among the most widely planted ornamental trees in both Europe and North America. They were particularly popular as a street tree in avenue plantings in towns and cities, creating high-tunnelled effects. Their tolerance of air-pollution and the comparatively rapid decomposition of their leaf-litter in the fall were further advantages. In North America, the species most commonly planted was the American elm (Ulmus americana), which had unique properties that made it ideal for such use: rapid growth, adaptation to a broad range of climates and soils, strong wood, resistance to wind damage, and vase-like growth habit requiring minimal pruning. In Europe, the wych elm (U. glabra) and the smooth-leaved elm (U. minor var. minor) were the most widely planted in the countryside, with the former in northern areas including Scandinavia and northern Britain), and the latter further south. The hybrid between these two, Dutch elm (U. × hollandica), occurs naturally and was also commonly planted. In much of England, it was the English elm (Ulmus procera) which later came to dominate the horticultural landscape. Most commonly planted in hedgerows, the English elm sometimes occurred in densities of over 1000 per square kilometre. In Australia, large numbers of English elms, as well as other species and cultivars, were planted as ornamentals following their introduction in the 19th century. From about 1850 to 1920, the most prized small ornamental elm in parks and gardens was the Camperdown elm (Ulmus glabra 'Camperdownii'), a contorted weeping cultivar of the Wych Elm grafted onto a non-weeping elm trunk to give a wide, spreading and weeping fountain shape in large garden spaces.

During the 18th and 19th centuries, elm cultivars enjoyed much popularity as ornamentals in Europe by virtue of their rapid growth and variety of foliage and forms. This "belle époque" lasted until the First World War, when the consequences of hostilities, notably in Germany whence at least 40 cultivars originated, and the outbreak of Dutch elm disease saw the elm slide into horticultural decline. The devastation caused by the Second World War, and the demise in 1944 of the huge Späth nursery in Berlin, only accelerated the process. The outbreak of the new, three times more virulent, strain of Dutch elm disease Ophiostoma novo-ulmi in the late 1960s brought the tree to its nadir.

Since circa 1990 however, the elm has enjoyed a renaissance through the successful development in North America and Europe of cultivars highly resistant to the new disease. Consequently, the total number of named cultivars, ancient and modern, now exceeds 300, although many of the older clones, possibly over 120, have been lost to cultivation. Unhappily, enthusiasm for the newer clones often remains low owing to the poor performance of earlier, supposedly disease-resistant Dutch trees released in the 1960s and 1970s. In the Netherlands, sales of elm cultivars slumped from over 56,000 in 1989 to just 6,800 in 2004, whilst in the UK, only four of the new American and European releases were commercially available in 2008.