Skip to Content

What is a Cucumber Tree?

A close look at the gnarled branches of a cucumber tree.

The American elm tree is truly something to behold — pendulous stalks create an enchanting umbrella canopy, older trees sporting characteristically fissured gray bark, soft elm leaves blowing in the breeze.

This tree species is truly a fighter and survivor — it has been attacked by Dutch Elm Disease, and many members of the American elm community have lived to tell the tale. What was once the most popular street tree in all of North America (certain areas of New York only have elms planted along the streets) has dwindled down to a precious few.

Trees are cool! And we’ve got a list of 101 Types of Trees to keep you busy. But if you’re more curious about Ulmus americana, read on and discover all of the factoids and details about this wonderful tree.

Ulmus Americana

Sometimes referred to as either white elm or water elm, the American elm is an incredibly hardy North American tree that can withstand temperatures as low as -44 degrees Fahrenheit. This tree is part of the Ulmus genus and is kin to other elm trees like the Chinese elm or lacebark elm (Ulmus parvifolia), Siberian elm (Ulmus pumila), and the slippery elm (Ulmus rubra). Read about 11 Types of Elm Trees here.

This large deciduous tree is very fast-growing and can prove to be quite long-living, as long as it isn’t infected by the Dutch Elm Disease (DED) that we’ll go into later. The oldest American elm on record grew along the banks of Sauble river in Ontario, Canada. It grew to be 43 meters tall, and live through the years 1701-1968. That’s 267 years!

Rows of giant American Elm trees in a park.

Are American Elm Trees Extinct?

Just now we mentioned the Dutch Elm Disease (DED) which has unfortunately brought the American elm into the endangered category. DED is a fungal disease brought on by sac fungi (Ascomycota) that are spread by these beetles:

  • elm bark beetle (hylurgopinus rufipes) – species native to North America
  • elm leaf beetle (xanthogaleruca luteola) – species native to North America
  • European elm bark beetle (Scolytus multistriatus) – invasive species
  • banded elm bark beetle (Scolytus schevyrewi) – invasive species
  • Japanese beetle (Popillia japonica) – invasive species

These beetles do not cause Dutch Elm Disease, but if they were to feed very intensely on an injured or sick tree, that alone may kill them. The reason why these beetles are involved with DED is that they are carriers of spores, which is how the disease is spread so pervasively.

It is said that only 1 out of every 100,000 elm trees is resistant to DED, meaning that the disease has caused an absolutely catastrophic die-off. The reason why most elms are so susceptible is that the time of year where the fungus thrives is the same time of year that elms experience the most growth — in the spring. With new springwood, all of their vessels are functioning in full force, and are vulnerable to infection.

Unfortunately, elms don’t only have one pest to deal with. They are also very susceptible to something called verticillium wilt, which has many similar symptoms to DED, but luckily the damage is far less serious.

So all of that to say that no, the American elm tree is not extinct, but it is severely endangered. Luckily efforts have been made to hybridized the elm with trees that are more tolerant of Dutch Elm Disease fungus. There are also a few pockets of places where the American elm is still able to thrive, where the fungus cannot thrive in that climate — these places are British Columbia and Alberta in Canada, and certain parts of Florida as well.

Additionally, the biological makeup of this tree has enabled it as more likely to survive a wide-spreading disease. Because the trees become sexually mature at a younger age, they are able to spread more seeds, which germinate quite quickly.

This was not the case for various species of ash trees that are currently being absolutely decimated by the emerald ash borer.

A close look at the tree trunk of an American Elm Tree.

What do American Elm Trees Look Like?

Beginning with what occurs under the soil, the American elm tailors the type of root system they require. In soil that is very moist and heavy, the root system will be very widely spreading and will grow only about 1 meter deep into the soil. If the tree is growing in dry soil, it will develop more of a taproot system. This type of root system is shared with carrots, where one single root will grow very deep into the soil to reach the water deep in the earth.

American elms are a very impressively large tree, growing to be an average of 30 meters tall and trunks that are over 1 meter wide. Their trunks are coated with gray bark. A young tree will have bark that is more gray-brown in color, with shallow diamond-shaped fissures. A mature American elm will have ash-gray bark that starts to come off in scales. The inner bark is a buff and lovely cream color.

The trunk leads up to the crown of the tree, which is a thick coverage umbrella canopy, making it an unbeatable shade tree. Branches are thick and far-reaching. At the ends of these branches, you’ll find slender, reddish-brown twigs that are delicately downy.

American elm leaves are alternately arranged with double serrated margins and a wide base. They sprout in the middle of spring and are dark green leaves. To learn about American elm tree flowers, read on to discover how they reproduce!

Tall mature American Elm trees in a park.

How do American Elm Trees Reproduce?

The flower of the American elm tree will emerge in the early spring before the leaves do. They are very small and bright purple color. The flowers from this tree are protogynous, meaning that they are able to change their sex at a certain point in the year.

Female flowers mature before male flowers do, making self-fertilization slightly more difficult. Otherwise, the tree can be wind-pollinated, since the tree possesses both sexual characteristics.

Once the tree is fertilized, a fruit will emerge in the late summer. The fruit is a flat samara, which is a circular paper wing that encompasses a single seed. These seeds are wind-dispersed, making it quite easy for the American elm to spread to many different habitats.

American elm seeds are able to germinate almost immediately and rarely lay dormant for longer than a year.

A close look at the seed pods of an American Elm tree.

Where do American Elm Trees Grow?

The American elm is a very cold hardy tree and is able to thrive in the bitter Canadian winters. Native to many places in North America, they occur naturally all the way from Nova Scotia to Alberta, from Montana down to Florida and Texas.

Once considered to be a street tree, they are no longer tolerant to urban areas (the city pollution making them more vulnerable to Dutch Elm Disease) they are likely to be found in a growing zone like along railroads, abandoned lots, and unpopular roads.

What are the Growing Conditions of American Elm Trees?

This elm cultivar is tolerant of so many kinds of habitats, which is saying a lot once you realize how particular certain species of trees can be. They tend to prosper best in swampy grounds, stream banks, rich bottomlands, and floodplains.

This indicates that they prefer soil that is incredibly moist and stays that way, that is relatively high in acidity, and is also well-drained. That being said, they are also able to thrive on hillsides and uplands as well.

When an American elm is found in regions that are high in elevation, they are most likely to be growing along riversides. It is very unlikely to ever find them in urban situations, as they have grown to be completely intolerant of city pollution.

In the United States, the American elm tree is a very important member of forest cover types, and will always be found growing amidst these tree species:

  • black ash
  • green ash
  • red maple
  • silver maple
  • sugar maple
  • sugarberry
  • sycamore sweetgum

A close look at the leaves of an American Elm tree.

How are American Elm Trees Used?

This tree is a very important food source for various lepidopteran species (moths and butterflies) and their larvae. The following species greatly rely on the foliage of the American elm:

  • mourning cloak (Nymphalis antiopa)
  • painted lady (Vanessa cardui)
  • Columbian silk moth (Hyalophora Columbia)
  • the eastern comma (Polygonia comma)
  • banded tussock moth (halysidota tessellaris)
  • red-spotted purple (Limenitis anthems astyanax)
  • question mark (Polygonia interrogationis)
  • gypsy moth (Lymantria dispar dispar)

For humans, the American elm was first and foremost an ornamental tree for a great many city streets, parks, and backyards. They were very tolerant of urban conditions, they grow very quickly, and the attractive way in which their canopy grows made it the choice of an ornamental tree.

However, urban planners didn’t take into account the dangers of over-planting, and of planting a strict monoculture of elms. No one can truly expect a horrible tree disease to spread, but planting only one species of tree, it makes all of them extremely vulnerable to these kinds of disastrous events.

Since they are an endangered species, American elm trees are no longer used for their wood, as the utmost priority is to keep the species alive. When they were prominent, elm wood was used to create baskets, woodenware, flooring, and furniture. Since the wood is so flexible but tough, it was also a very popular choice in the creation of hockey sticks!

A close look at the branches of American Elm trees.


Are American elm trees messy?

The American elm tree is a deciduous tree, so that means that it sheds its leaves every fall to prepare for the winter months ahead. If you have this tree in your yard, it is likely to shed every year not only in the fall but when it releases its winged seed pods as well. These pods are usually what cause the most damage, as a mature tree can release millions in a season.

If you’re concerned about having a tidy lawn, consider investing in a coniferous tree, these do not shed their foliage.

When do American elm trees bloom?

The flowers of an American elm tree will bloom in the early spring before the new spring foliage emerges. Once the flowers are pollinated, the fruit will emerge in the late summer.

How do you identify an American elm tree?

The best ways to identify an American elm are either by its large canopy that is far-reaching and droops down like an umbrella or by its small purples flowers that can be found in the very early spring.

Otherwise, American elm bark is gray but has diamond-shaped, elliptical fissures that are quite noticeable. If you’re really desperate, look at a twig — if it is reddish-brown and slightly hairy, you’ve got yourself an American elm.

How long do American elm trees live?

As long as an American elm isn’t subjected to Dutch Elm Disease, it is able to live hundreds of years — putting this species of tree in the old-growth category. The oldest elm tree on record lived in Ontario and lived to be 267 years old before it was killed by DED.

How fast do American elm trees grow?

American elm trees are incredibly fast-growing, with the ability to grow anywhere between 2-4 meters in height every year — this quick growth is supported by an equally girthy trunk, which will get to be over 1 meter thick in its lifetime.

What killed the American elm trees?

The American elm tree is incredibly susceptible to the Dutch Elm Disease caused by the sac fungus Ascomycota.

What is another name for an American elm?

American elms also go by the nicknames of white elm (because of their cream-colored inner bark) or water elm (because they are most commonly found growing near large bodies of water, or very water-logged soils).

How long do American elm tree seeds stay dormant?

The seed of an American elm is able to germinate immediately and usually doesn’t hesitate to do so. That being said, the seed can stay dormant for up to a year before it should germinate.

Is elm a softwood or hardwood?

They are actually classified as “soft” hardwoods because they are not quite as hard as other American hardwoods, but they are not soft enough to be considered as a softwood tree.