and Deciduous Forest Trees
of Southern Ontario

Slippery Elm
Ulmus Rubra

Location in Ontario:
Slippery Elm trees grow throughout the Deciduous Forest Region, and further north.

Slippery Elm, Backus Woods, Norfolk County

Genus Ulmus:
  The leaves of Elm are asymmetrical. The overall form of Elm trees is an umbrella shape, White Elm with the most pronounced. Elms are monoecious with perfect flowers in dense clusters. They appear in very early spring. Seeds are nutlets contained within a thin wing (samara). Nutlets are deeply notched and fall off in May. In Ontario, this genus includes Rock, Slippery and White Elm.

Dutch Elm Disease was accidentally brought to Canada in 1944, via wooden crates. White Elm are the most affected by the disease. Once a tree is infected, nothing can be done. Preventative pesticides can be used but are costly. Development of a disease resistant hybrid has been unsuccessful. White Elm trees once lined many streets in Southern Ontario. Today, only a few stately Elms can still be spotted, indicating some immunity to the disease. Elm trees produce abundant seeds every year, and the seeds easily germinate. This has helped Elm to survive Dutch Elm Disease.

Dutch Elm Disease History  

Habitat: Slippery Elm grows along rivers and streams.

Landscape Use:
If an Elm tree is planted, care must be taken to avoid Dutch Elm Disease. Slippery Elm has attractive reddish-brown bark, but is not often seen as a landscape tree. It has the typical Elm umbrella shape, but less symmetrical than White Elm.

Leaves: Slippery Elm leaves are simple, with double teeth. The leaves are asymmetrical in shape. They have a rough, sandpaper feeling on the top, and are hairy beneath.

FALL COLOUR WATCH: yellow to brown 

Flowers: Slippery Elm is monoecious with perfect flowers. Flowers are tiny and light coloured, and found in dense clusters. They appear in very early spring.

Fruit: Slippery Elm seeds are nutlets contained within a thin wing (samara). Nutlets are deeply notched and fall off in May. Slippery Elm produces fruit after 15 years of growth with good seed crops every 2 to 4 years.

Bark: The bark is reddish-brown with scaly ridges.

Reddish colour of Slippery Elm, Backus Woods,
Norfolk County

TREE FACT: Slippery Elm is named for the "slippery" feel of the inner bark. It is also known as Red Elm for the reddish tone to the bark.

Size: This is a medium sized tree, growing up to 25 metres and living to 125 years.

Genetics:  Slippery Elm is diploid, with 28 chromosomes.

Wood: Slippery Elm wood is hard and heavy, but less than the other Elms. Elm wood was favoured for wheels, hockey sticks and boat frames.
Specific gravity: 0.53
Janka Hardness: 860 lb

Wood Comparison Chart