Slippery Elm
Ulmus rubra

Location in Ontario

Slippery Elm trees grow throughout the Deciduous Forest Region, and further north. It grows along rivers and streams.


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 has killed many elms (see Tree Diseases)).

TREE FACT: Elms flower very early in the spring, second only to Red and Silver Maples.

In the Landscape
Slippery Elm is a medium sized tree, growing up to 25 metres and living to 125 years. 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.

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 


Reddish colour of Slippery Elm, Backus Woods, Norfolk County

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. The leaves turn yellow-brown in the fall.
Bark
The bark is reddish-brown with scaly ridges.
 
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 before the leaves. Flowers are wind pollinated.
Fruit
Slippery Elm seeds are samaras (nutlets contained within a thin wing). Samaras are deeply notched and develop quickly after the flower is pollinated. They fall off in May. Slippery Elm produces fruit after 15 years of growth with good seed crops every 2 to 4 years.
 

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

Genetics
Slippery Elm is diploid, with 28 chromosomes.


Slippery Elm leaves, Norfolk County

Link to United States Forest Service Silvics Manual for Slippery Elm.

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