A Gardener’s Guide to the American Elm
Also known as the Water Elm and the White Elm, the American elm is one of the most hardy and tallest growing North American trees alive right now. Amazing shade providers and eye catchers, many people and corporations choose to adorn their properties with this tall and magnificent species of tree.
This type of elm is a deciduous tree, and prior to Dutch elm disease one could see them growing to be over 100 ft tall and 4 ft in diameter. This type of tree features a large, spreading canopy at the top with plenty of open space beneath it to show off its formidable branches. So beautiful and awe-inspiring is this tree that it is the official state tree of both North Dakota and Massachusetts.
In the early spring, small purple-brown flowers can be seen, followed shortly by the tree’s leaves. The leaves can be anywhere from 7 – 20 cm in length. They boast double serrated edges with an oblique base. During the fall you can see its leaves changing to beautiful autumn colors, and with as large as the tree is, one can imagine just how majestic that sight is.
Because this tree has “perfect flowers,” it is considered to be hermaphroditic, and can therefore pollinate itself. The flowers, called samaras, resemble a child’s version of a helicopter toy and float off in the wind. These flowers are about 2 cm long and house two circular shaped wings that aide in “flight.” The tree does not reach sexual maturity, however, until around the age of 150 years.
The American elm was once considered to be among the hardiest of trees around. In regards to weather, it still is. In fact, it can withstand temperatures as low as – 44 degrees Fahrenheit, allowing it to grow as far north as Nova Scotia and other parts of Canada as well. It can also maintain its leaves well into fall, only beginning to lose them as damaging frosts come into play.
Problems with Dutch Elm Disease
Unfortunately, the American elm is quite susceptible to Dutch elm disease. This disease has a tendency to run rampant through American elms, and because of it, many of this species never even get to reach full sexual maturity. Whereas American elms once commonly grew for at least 200 years, the trees now only grow to about 100 if Dutch elm disease has a chance to set in.
Thankfully, American elms have been able to survive, despite the ravaging damage of this fungal disease. It is estimated that approximately 1 in 100,000 American elms is immune to this disease, and tree enthusiasts and researchers are hoping that somehow down the line, the trees will hybridize and a new species of disease resistant American elms will grow.
It should be noted that despite this fungal disease, the trees can still live a long time and are therefore still handy to use in private and public property, as they will last many decades.
Because of their sheer size, the American elm has been commonly used on private property as a shade tree. Many city planners have taken note of their longevity and strength, though, and have chosen to include them in city planning as street trees. Because they grow quite quickly, the cities and towns don’t have to wait generations to see the trees in all of their glory, taking an ordinary street and turning it into a pleasant and shady avenue for the occasional leisurely stroll. Many college campuses in Northeastern America feature single specimens or small groves of these as well.