Ulmus

There are 45 species of Elm and these come from most of the temperate northern regions of the globe. Elms have been stricken by 'Dutch Elm Disease' which has removed most Elms from the British landscape. The disease is caused by a fungus which is transported by the Elm beetle which lays eggs in the bark of trees. Elm trees continue to regenerate from suckers, but, at around twenty years they are mature enough to be attractive to the beetle and are then decimated. The epithet 'Dutch' was applied because it was the Dutch who conducted early research on this disease. Its introduction to the UK was not from Europe but from North America, arriving in infected logs. A number of Elm species are still grown - Ulmus parvifolia the Chinese elm is highly resistant, and there are a good range of worthy cultivars that include forms with variegated foliage. Although Ulmus glabra is susceptible to the disease, a number of forms such as the shrubby Ulmus minor 'Jacqueline Hillier' that takes years to reach 4 metres in height, last for many years in isolated gardens. There are a number of new cultivars that have shown good disease resistance such as the upstanding Ulmus 'Doedens'.