Fiorente and Arno elm trees.

Dutch elm disease (DED) has spread through Europe since the beginning of the 20th century. Several independent genetic improvement programs for breeding DED-resistant elms have been established in Europe. The Italian elm breeding program began in the late 1970s with the goal of hybridizing susceptible European elms with resistant Asian species to select DED-resistant clones suited to the Mediterranean climate. Ulmus ‘Fiorente’ and ‘Arno’ are two new releases selected for DED resistance, superior growth rate, attractive foliage, and upright habit.