Tree of the Month: Frontier Elm
What to Know About the Frontier Elm
Frontier Elms
Elm trees can be found across the northern hemisphere, and while many were decimated in the twentieth century by Dutch elm disease, elm tree varieties have since been bred by nurseries to be resistant to the disease. The Frontier elm is one such cultivar, and it’s prized not just for its resilience but also for its more compact size, urban hardiness, and beautiful burgundy foliage in the fall. Here, we’ll go over why this elm tree has become such a popular planting choice.
Cultivated for Resilience
Since it was first noticed in Europe in 1910, then in the U.S. in the 1920s, tree scientists have been working hard to save the elm tree from total devastation by the fungal Dutch elm disease, which is spread by elm bark beetles that carry the pathogen on their bodies as they move from tree to tree.
The Frontier elm is an American-bred cultivar, the outcome of research led by the U.S. National Arboretum. The tree’s scientific name is Ulmus minor x parvifolia, reflecting its European and Asian elm sources. The resulting hybrid species is not only resistant to Dutch elm disease but also has many other unique attributes that make it a hardy, desirable tree:
Some resistance to elm yellows – Another fungal pathogen, this one is spread by leafhoppers that feed on elm tree leaves. The infection results in rapidly yellowing leaves (chlorosis) from the fungal infection that prevents nutrients from circulating through the tree. The unseasonable leaf drop (usually in summer) is a major sign the tree is stressed and/or sick.
Tight form compared to other varieties of elm – The Frontier elm is a shorter variety than other elm trees, and its crown doesn’t reach out quite as wide. This compact form makes it easier to grow in locations where bigger elms may not have the space they need to spread out.
Low to no seed production – This elm hybrid produces very few seeds, if any, which makes it less messy than trees that put out and drop lots of seeds each year.
Soil and salt tolerance – Another great feature of this tree is its ability to tolerate a range of soils and saltier than average ground, a common condition of urban soil.
How Fast Do Frontier Elm Trees Grow?
A medium-sized canopy tree, the Frontier elm grows at a medium rate, taking on one to two feet per year until it reaches a mature height of 40 feet on average, with the crown getting about as wide as the tree is tall. This cultivar is smaller than other elms; compare its size to the American elm (Ulmus americana), whose mature height is 80 feet, with a broad, outstretched crown.
Visual Features of the Frontier Elm Tree
The Frontier elm has branches that reach upward, creating an oval or pyramid shape that contributes to its more compact nature. In the summer, a Frontier elm’s branches are filled with green leaves that are characteristic of elms in general: serrated, single-lobed leaves with straight, diagonal veins that reach to the edges of the leaf. However, unique among elms is the Frontier elm’s fall color, a gorgeous deep red (other elm trees turn a golden yellow in the fall).
Like other elms, the Frontier likes to be in full sun and does best in moist, well-draining soil. However, the tree also has some tolerance for dryness and occasional drought.
Frontier Elm Pros and Cons
From improved air quality to providing habitat for all types of wildlife, the Frontier elm provides the range of ecosystem services and resulting benefits that other canopy trees do. Wherever they are planted, their roots help hold the soil in place, and their bushy summer foliage provides cooling shade in the warmest and brightest months of the year. In the winter, after their showy autumnal color fades, Frontier elms drop their leaves and allow sunlight to reach the ground throughout the cool months, allowing a little more heat and sunshine during the day in the cold, darker parts of the year.
When it comes to the Frontier elm, there really are no drawbacks! This tree was bred to be a robust species that will thrive along streets, in residential yards, and in neighborhood parks. Its high resistance to diseases and pests, attractive year-round visual appeal, robust environmental tolerances, and general contribution to the wider canopy system make this tree a fantastic choice for any landscape!
Check out our listing for the Frontier elm through Nashville Tree Conservation Corps’ tree sale! If you’re not in the market for a new tree, you can still help us care for and build Nashville’s canopy by volunteering with us! For the latest on NTCC’s activities, tree news, and care tips, sign up for our email newsletter and stay connected with our regular updates.