The fungus that causes the disease is spread by certain species of the elm bark beetle. Although many elms have survived, the disease eventually kills those trees that are susceptible unless the beetle is controlled by sanitation, spraying and pruning. Some American elms, and other elm species, that have survived and have not been infected are considered resistant. Clones of these resistant American elms and hybrids of resistant species are being developed, produced and used to replace the old trees that were lost. Even though the use of all elms has diminished because of Dutch elm disease, the elm may regain its favored status with the introduction of these new resistant selections.
Elms prefer full sun to part shade.
Although they grow best when grown in moist, well-drained, fertile soil, they adapt to most soil conditions wet or dry, alkaline or acidic. Because they tolerate urban conditions, they are good selections for street trees. Their roots are shallow, however, and can cause concrete sidewalks to buckle. Root barriers should be installed when planting in tight areas. Select trees with major branches spaced along one trunk.