"Allee Elm" refers to a specific cultivar of American Elm (Ulmus americana) known for its upright, columnar growth habit, making it particularly suitable for use in alleys, streetscapes, and other urban settings. The term "allee" itself refers to a tree-lined avenue or walkway, and the Allee Elm is often chosen for its ability to create a formal, uniform appearance in such settings.

Here are some key features of the Allee Elm:

1. Appearance: Allee Elm trees typically have a tall, narrow form, with a tight, upright growth habit. They can reach heights of up to 40 to 70 feet, with a spread of only 20 to 30 feet. The crown is more columnar than the typical spreading form of American Elm.

2. Leaves: The leaves of the Allee Elm are similar to those of the American Elm, being ovate or elliptical with serrated edges. They are dark green in color and turn golden-yellow in the fall before dropping.

3. Bark: The bark of young Allee Elm trees is smooth and grayish-brown, becoming deeply furrowed and ridged with age, similar to the typical American Elm.

4. Landscape Use: Due to its tall, narrow form, the Allee Elm is often used for lining streets, avenues, or pathways, hence its name. It can also be used as a specimen tree in large landscapes or as part of a formal garden design.

5. Maintenance: Like other elm trees, the Allee Elm is relatively low-maintenance once established. Regular watering, especially during dry periods, and occasional pruning to remove dead or damaged branches are typically sufficient to keep the tree healthy and looking its best.

Overall, the Allee Elm is valued for its attractive appearance, resistance to Dutch Elm Disease, and suitability for use in urban landscapes, particularly where space is limited and a formal, uniform aesthetic is desired.