Full-grown American elm trees are difficult to locate, though the species at one time was very widespread throughout the eastern half of the United States. Disease took its toll on the elm, a tree that the "National Audubon Society Field Guide to Trees" describes as "handsome and graceful." The leaves of the elm are distinct in their appearance. Identifying elm leaves is simply a matter of knowing what to look for.
Elm leaves have an elliptical shape, with the leaves sometimes possessing a slightly curved appearance. The ends come to a distinct point. Elm leaves grow to be 4 to 6 inches long. Their widths vary between 1 and 3 inches, with the elm leaf at its widest in its middle. One aspect of the American elm tree is that the leaves can differ in size from one specimen to another; on some the foliage may be smaller than it is on one right next to it.
Bases and Stems
Growing alternately along the twigs, the elm leaf has a base that is not symmetrical. One side of the base will meet the stem lower down than the other side, sometimes by as much as a quarter inch. The stems to which the elm leaves attach are very short, sometimes less than half an inch long.
The edges of the elm tree's leaves have serrations all along them, giving the leaf the look of an oval saw blade. The veins are obvious on American elm foliage. The Ohio Department of Natural Resources describes the veins as being prominent, noting that they run from the midrib of the leaf out to the sides.
The upper-facing side of an American elm leaf has a dark green color. That side is typically hairless or just a bit rough. The underside of an elm leaf takes on a paler shade of green, with the presence of minute soft hairs noticeable upon very close examination. In the fall, the elm will change to yellow in good years for color, while in other years the leaves turn chartreuse before falling.
The American elm tree suffered a terrible fate, with the tree's problems beginning around 1930 when a shipment of logs from Europe triggered a still-ongoing outbreak of Dutch elm disease. This fungal ailment, carried onto the tree by beetles, had the effect of destroying nearly every mature elm in the United States. Once an elm reaches a certain size and age, it falls victim to this malady. The leaves are among the first features of the elm to show signs of Dutch elm disease, as they slowly will wilt and change to yellow. The leaves then fall off and entire sections of the tree die.