There are very few trees associated with America more than the elm. One species of elm is even called the American elm. However, over the years this popular tree has faced an increasingly difficult battle against the Dutch elm disease which has wiped out the species in entire communities. Still, despite reports to the contrary, the elm tree is not dead and may be poised for a comeback.
There are more than a half-dozen species of elms. The American elm is one of the most well-known species. Other types of elms include the rock elm, slippery elm and Scotch elm. Elms enjoy a wide distribution and some are native to Europe and others native to various portions of Asia. The name often provides some clue as to where the tree is commonly found.
There is a great range in size of elms. Though conditions will play a role in the overall height of the tree, the species of the elm is often the most important factor. Camperdown elms may reach heights of only 10 feet whereas slippery elms, one of the largest in the elm family, can reach heights of up to 132 feet. Heights of 110 to 130 feet are common for many elm varieties
Elm trees typically have serrated leaves, which taper off to a fine point. The trees have a single, distinct trunk that runs nearly to the top. Most also spread out to a diameter of approximately half the size of the height. However, rock elms, which are found mainly in the Midwest United States, maintain a very narrow shape and are considered relatively rare among the elm varieties.
If you are planning to care for an elm, there are a number of important things to keep in mind. Elm trees should be fertilized twice a year. The fertilizer should allow for a slow release of nitrogen to help encourage proper growth. The tree should also be watered thoroughly, but allowed to dry between waterings. If you are planting an elm, be sure that you have allowed enough clearance to account for its full growth, which means avoiding obstructions such as power lines.
Dutch elm disease is a fungal infection often spread by insects and humans. Although some elms can resist the disease, the American elm and a few other species are nearly totally defenseless. If you have a branch that unexpectedly dies, have it tested immediately. If the test comes back positive, the entire tree may need to be destroyed to prevent other trees from getting the infection.