Carolinian
and Deciduous Forest Trees
of Southern Ontario

Butternut
Juglans Cinerea

Location in Ontario
: Butternut (White Walnut) grows throughout the Deciduous Forest Region and further north. However, due to Butternut canker, many trees have died, making Butternut scarce today.

COSEWIC (Committee on the Status of Endangered Wildlife in Canada) Status: Butternut is identified as a Endangered Species in Canada. This is due to loss of trees to Butternut Canker.


Large and small roadside Butternuts, Chatham-Kent

Genus Juglans: Walnuts as a genus have compound, alternate leaves with 11 to 23 leaflets. They are monoecious with male (pollen) flowers and female (seed) flowers on the same tree. Large, edible nuts are produced. The wood is treasured for the colour and grain. In Ontario, Black Walnut and Butternut (White Walnut) can be found. 

How Can You Tell Walnuts apart??
Black Walnut bark has dark furrows, Butternut is lighter with flat-topped ridges. Black Walnut leaves have smaller bottom leaflets, and the top leaflet is often missing. Butternut leaflets get narrower along the leaf. Walnuts are round, Butternuts are oblong and pointed.

Habitat: Butternut likes well-drained, rich soil.

Landscape Use: Butternut is a pretty landscape tree with attractive bark and compound leaves, however, it is risky to plant due to high risk of Butternut Canker.

Butternut Canker

This devastating fungus spreads quickly and has infected most Butternut Trees in North America. Its origins are not known, but suspected to be from Asia. Once a tree is infected, not much can be done, and the tree eventually dies. This can take up to 40 years, with younger trees dying more quickly. About one third of Butternut in Ontario have already died due to the canker, and many of the remaining Butternut are infected.

Visit this site for more information:
Forest Invasives Canada

Leaves: Butternut has compound leaves, with 11 to 17 leaflets.

FALL COLOUR WATCH:  yellow

Flowers:
Butternut is monoecious with male (pollen) flowers and female (seed) flowers on the same tree.  Pollen flowers are small and green, and found in long catkins. Seed flowers are in clusters at the end of a new shoot. Flowers appear in May.

Fruit: The fruit is an edible, hard nut with a green husk. Butternuts have sweet nuts, that are elongated spheres with pointed ends. Nuts are produced every 2 to 3 years after 20 years of growth.

TREE FACT: Black Walnuts and Butternuts are both edible, Butternut being the more tasty of the two. Butternut nuts can be boiled and the oil skimmed off to make a type of butter, hence the name "butternut".


Leaves and fruit

Bark: The bark is light gray with narrow fissures.

Size:  Butternut is a medium sized tree that grows up to 25 metres.

Wood: Butternut wood is of medium hardness, much less than Black Walnut. It does have a nice grain, and has been used for furniture.
Specific gravity: 0.38
Janka Hardness: 490 lb
Wood Comparison Chart


Giant Butternut in flower, St. Williams Nursery and Ecology Centre

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