American Elm (Ulmus americana)

American elms on Elm Rock, May 2020

Near the southwest corner of the farm is a large, pinkish, granite stone; a remnant of the earth’s crust exposed by the slow journey of an ancient glacier. Growing from this rock are three mid-sized elm trees, their roots emerging tenaciously from fissures in the stone. This rock is the namesake of Elm Rock Farm, and these three American elms are the salient landmarks when looking east from the yard site.

Prized for their massive canopies, elms were planted abundantly along city boulevards throughout the 19th and early 20th centuries, until dutch elm disease became prevalent throughout the 1900s. Today, elms are still plentiful in urban arboriculture, but the disease is kept in check through a combination of aggressive pruning and fungicidal treatment. Interestingly, Winnipeg is thought to be the home of the largest urban elm population in North America, with roughly 230,000 individual trees. Elms planted on opposite sides of many Winnipeg avenues reach across in a leafy handshake, lending a peaceful shade to the neighbourhood.

The wide, dense crown also provides a vibrant habitat for wildlife. I have spent many hours laying on Elm Rock, watching an endless melody of birds explore the labyrinth of branches, leaves and samaras above.

Kipling apparently had a more sceptical view, as evinced in “A Tree Song”:

Ellum, she hateth mankind, and waiteth

Til every gust be laid,

To drop a limb on the head of him

That anyway trusts her shade.

Fortunately for those averse to branch-induced concussions, the beauty of the elm can also be appreciated from afar. As the sun descends below the western tree line, I often gaze out into the field, and watch the shadows overtake those three titans growing improbably from the rock.

Other Common Names:

  • White elm


  • Deciduous tree, grows 24-30m
  • Dark grey bark, deeply ridged in older trees. Twigs are alternate, tending to zig zag.
  • Leaves are simple, alternate, and 7-20 cm long, with doubly serrate margins. Leaf base is asymmetrical, and petioles and undersides of leaves are hairy.
  • Buds are oval, reddish brown. Scale edges are darker, and can be hairy. Flower buds are smaller than leaf buds. The terminal bud is always a leaf bud.
Young leaves of an American Elm. Elm Rock Farm, 2017


  • Flowers contain both male and female parts: small, purple-brown with no petals. The female parts mature before the male parts, reducing self-pollination. Emerge in early spring, before the leaves.
  • Flowers and seeds are on a 1-3 cm stem
  • Wind pollinated.
  • Fruit is a flat, green/yellow, circular, notched samara, 1.25 cm long, with hairy edges, ripening in spring. A single seed is encased in each samara.
  • Seed production may begin as young as 15 years old, becoming abundant after 40 years.

Similar Species:

  • Siberian Elm (U. pumila)
    • Siberian elm is a smaller tree, often bushy, growing only to 20m.
    • The leaves of Siberian elm are much smaller than American Elm, less than 7 cm long.
    • The leaves of Siberian elm are nearly symmetrical at the base, and singly serrate, while American elm leaves are asymmetrical and generally doubly serrate.
    • Samaras of U. Americana have hairy edges, while those of U. pumila are hairless.
    • Flower buds of Siberian elm are nearly spherical.

Ecological Role:

  • The larvae of several butterflies and moths feed on elm leaves.
  • Flower buds, flowers and fruit are eaten by squirrels.
  • Seeds eaten by various rodents and birds.


  • Seeds
  • Young leaves
  • Inner bark

Other Uses:

  • Durable wood, used for furniture, boats, pallets, boxes, etc.


  • “Elm” is derived from Latin “Ulmus,” which is derived from an ancient name for elm trees.


  • American elm was devastated by the introduction of Dutch elm disease to North America around 1930. It is caused by a fungus which is spread tree to tree by beetles.

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