Habitat:
Hardy from zone 2 to 9, the American elm prefers rich, moist soils along
river valleys and is absent in mountainous areas and on high land. It once
dominated the flood plains of Iowa, and young trees (not yet attractive
to bark beetles) may still be found there. It adapts to a variety of conditions
and is moderately shade tolerant, moderately pH tolerant and soil salt will
not adversely affect this species.
Diseases: Elm bark beetles are responsible for spreading Dutch elm disease. This disease, first seen in the Netherlands in 1919, was introduced to the US from Europe and causes wilting, yellowing, leaf curl and eventual death of infected trees. Dark flecks are visible in infected sapwood near the bark in cross sections of twigs. This disease has killed over 40 million landscape elms in the US since the 1920's. There is no cure, but early community-wide detection, sanitation and removal of affected trees can limit its spread. Cultivars resistant to the disease are available for purchase, but none equal the beauty of the true species. Bacterial wetwood, Verticillium wilt, cankers, elm case borer, elm leaf miner and elm borer may also be problematic.
Distribution: This is an eastern species, ranging from southern Canada to central Florida, west to the foot of the Rocky Mountains. It is native throughout Iowa.
