Ash Trees of Ontario

Ash Ttree in autumn

Ash Trees of Ontario – Fraxinus

While out walking on my own property I couldn’t help but notice how many ash trees I have. As well as full grown trees there are many babies. So far I have seen no sign of the dreaded Emerald Ash Borer but wonder how long before that happens. Will my baby ashes be able to survive?
Considering that I may someday lose my ash trees I decided to learn more about them.
There are four species of ash common to eastern Canada: Fraxinus nigra – black ash, Fraxinus americana – white ash, Fraxinus pennsylvanica – red ash and Fraxinus quadrangulata – blue ash.
A distinctive feature of ash trees is their opposite branches and compound leaves.
Ash trees like well drained fertile soil, pH 6.0-7.5 but will grow in a variety of locations. They can be grown from seed and are easily transplanted; can be coppiced and pollarded.

Black Ash – Fraxinus nigra is a medium sized tree commonly found in swamps, often with green ash. The leaves are opposite, pinnate with no stalks and have 7-13 (mostly 9) leaflets with finely toothed margins. Fall foliage is yellow and is one of first to lose its leaves. The black ash is in decline and is rarely found in wild.

White Ash – Fraxinus americana is the largest of the native ash species and is the most common in Canada. It is abundant around Great Lakes and upper St Lawrence River Valley. It is a forest tree often growing with maples. The leaves are opposite, pinnate with very short stalks and 5-9 (mostly 7) leaflets with no teeth. Fall foliage is bright red purple.

Red Ash – Fraxinus pennsylvanica ( also called Green Ash in US) is a medium sized tree that prefers stream banks and disturbed areas. Leaves are opposite, pinnate with 5-9 (mostly 7) leaflets with serrated margins from middle of leaflet to tip. Fall leaf colour is yellow that starts changing in early September. Leaflets are dropped one at a time.
Red ash were widely planted in urban areas to replace elm trees because they tolerate pollution, salt, drought and a wide range of growing conditions.

Blue ash – Fraxinus quadrangulata is a rare medium sized tree found around Thames River in London ON area and on Point Pelee growing in fields and open areas. Leaves are opposite, pinnate with 5-11 (mostly 7) leaflets that are elongated, oval and coarsely toothed. Twigs are square. The blue ash appears to be slightly more resistant to Emerald Ash Borer.

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