What to Know About the Elm Tree

Elms in Your Neighborhood

Nashville is filled with Elm trees, whose majestic spreading canopies provide shade in many parts of the city. If you’ve heard about Dutch Elm Disease, you might be reluctant to plant one of these beautiful trees in your yard, but the risks from the disease are minimal if you choose the right cultivar.

According to Nashville Tree Conservation Corps board member and certified master arborist at Bartlett Tree Experts, Michael Davie, Dutch Elm Disease is actually fairly unusual in our area. “It does show up here and there, but it isn’t a very common problem,” he says. In fact, Davie estimates he sees only one or two cases per year. It’s not completely understood why most Elms are not bothered by the disease, but it may have to do with their genetic makeup.

Genus Ulmus

The Elm is a deciduous tree that has a broad range of distribution across the northern hemisphere. In the U.S., species can be found across Northern and Southern states alike. Davie explains, “there is more diversity of Elms in the South than the North, and this might be due to the fact that there were no glaciers here to clear an area to be repopulated by whichever species could make it. Even though the tree is successful in a lot of places, there seem to be more of them around in the Southern states specifically.” 

There are five native species of Elm that can be found in the Nashville area: American, September, Winged, Rock, and Red Elms. There are also some non-native Elm species, the most common of which is the Lacebark Elm from Asia. When Dutch Elm Disease arrived in the United States from Europe in the early 20th century, it killed hundreds of thousands of native Elms, especially in the northern part of the country. 

What Is Dutch Elm Disease?

The European Elm Bark Beetle is the most common vector of this fungal disease. 

The disease occurs when the fungus spread by the beetle causes vascular wilt. Wilting of the leaves occurs when the tree’s defenses create a blockage to respond to the infection, which builds up in the tissue and blocks water and mineral flow to the leaves in the crown of the tree. “You can usually tell when Dutch Elm Disease has taken hold in a tree,” Davie says, “when you see one branch discoloring and wilting, some leaves getting dark or yellow, and starting to fall off.” This is known as “flagging,” when one branch’s infection gives it a distinctively sick look compared to the rest of the tree.

Dutch Elm Disease usually isn’t an immediate killer of trees, and when an isolated branch can be identified and removed, the tree can be treated and nursed to recovery. As with many pathogens, the disease is more of an issue for stressed trees, so keeping your trees in healthy condition is a simple way to resist Dutch Elm Disease. 

Elm Yellows

A bigger problem in Elm trees is a disease called Elm Yellows. This disease acts similarly to Dutch Elm but affects the entire crown of the tree. In this case, the disease takes hold at the root and can easily spread between neighboring Elms whose roots are touching. Elm Yellows can affect a whole area, while Dutch Elm tends to affect a single tree at a time.

What Can We Do to Keep Elms Healthy?

As a homeowner, the best thing you can do is avoid planting the Elm cultivar type that is most susceptible to Dutch Elm Disease. Michael advises avoiding the Princeton cultivar of the American Elm. Otherwise, his outlook on Dutch Elm is that it’s a “common worry, but not one to be too concerned with.” Concerning Elm Yellows or any other disease, he assures us that arborists will jump on it if they see infection on a tree. having your trees inspected every year or two by a certified arborist will help keep them in the healthiest condition.

NTCC’s Farm-to-Yard Tree Sale, which will resume deliveries in October, offers two different kinds of Elms. The Colonial Spirit cultivar of the American Elm is a beautiful large tree that can reach 60 feet in height with a 40-foot canopy. It is resistant to Dutch Elm Disease. Another choice is a smaller tree from the Elm family, the Frontier Elm, which grows to about 40 feet and is also disease resistant. Order a tree today and do your part to build our community’s tree canopy!

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