White Ash Characteristics

Size and Form

• When the white ash tree is young, it features an upright but oval shape. Age changes its form, giving it a more spreading or rounded canopy. White ash grows to 70 feet, with widths up to 50 feet. The trunks average between 12 and 24 inches in diameter.

White Ash Foliage

• Leaves on the white ash are compound. A rachis, or long, central stem, has between five and nine leaflets growing out of it to comprise each individual leaf. The rachis measures between 8 and 15 inches long, with leaflets as lengthy as 6 inches. Leaflets develop opposite one another on the rachis, with the exception of the odd leaflet growing at the end. They possess a shape like a spear point, with either fine serrations along the edges or none at all. The upper surface is dark green, but white ash gets its name from the undersides of its leaflets, which are shades of greenish-white. The leaves turn yellow and purple in autumn.

Flowers and Fruit

• Flowers bloom on white ash during April, with the tree having both male and female specimens. The flowers are tiny and of little ornamental value. Consider purchasing a male white ash tree to avoid the problem associated with cleanup of the white ash samaras, or seeds, that emerge on female trees. Tan and shaped like miniature paddles or keys, they form in clusters before dropping around the tree in the fall.

More Characteristics

• Bark on a white ash is smooth when the tree is young, but diamond-shaped furrows develop on the tree as it gains age. A characteristic of white ash is that it handles poor quality soil, growing to fruition where other types of trees would not. In the spring, you may notice shriveled and dying foliage on a white ash, the result of a disease known as anthracnose. Wet weather precipitates this malady, which is a fungus that affects the leaves.