Ohio Trees

Bulletin 700-00

Fraxinus – Ash

Ashes are large, deciduous trees with brown or black winter buds having one to two pairs of outer scales. Leaves are opposite and pinnately compound. Flowers are perfect or unisexual. Fruit is a one-seeded nutlet with elongated wings.

Key to Fraxinus Species

Description of Species

White Ash–Fraxinus americana

The white ash is found throughout the state, but reaches its best development on the heavy, clay soils in northeastern Ohio. In the southeastern part of Ohio, it is limited to the streams and lower slopes. It reaches an average height of 50—80 feet and a diameter of 2—3 feet, though much larger trees are found in virgin forest. Numerous cultivars are available in the nursery trade. Cultivars are marketed for purple fall color. White ash is drought-sensitive in woods and the landscape and should be avoided in drought-ridden sites.

Leaves are opposite and odd-pinnately compound. The leaves of the white ash are from 8—12 inches (20—30 cm) long and have from five to nine plainly stalked, sharp-pointed leaflets. Leaflets are 3—6 inches (71/2—15 cm) long and 1—3 inches (21/2—71/2 cm) wide. Leaflets have entire or slightly toothed margins and have fewer teeth than green ash. Foliage is dark green and smooth above, and pale green beneath. Fall color ranges from yellow through brown to a deep wine color and may be showy.

White Ash

Branches are round. Winter buds have one to two pairs of outer scales. Leaf scars are half-round and are usually deeply notched at the top. The first pair of lateral buds usually occurs at the base of the terminal bud. The mature bark varies in color from a light gray to a gray brown. The narrow ridges are separated regularly by deep, diamond-shaped fissures.

The flowers are usually of two kinds on different trees. The male is in dense, reddish-purple clusters while the female is in more open bunches. The fruit of the ash is winged, 1—11/2 inches (25—38 mm) long, and resembles the blade of a canoe paddle in outline with the seed at the handle end. The fruits mature in late summer and are distributed effectively by the winds.

The wood of the white ash is extremely valuable because of its toughness and elasticity. It is preferred over all other native woods for small tool handles; athletic implements such as rackets, bats, and oars; and agricultural implements. It is also used extensively for furniture and interior finish. Interestingly, the dead wood of ash loses its strength and becomes dangerously unstable.

Biltmore Ash–Fraxinus biltmoreana

The biltmore ash is similar to, but smaller than, the white ash. Distribution is principally in western Ohio and largely confined to the southwestern portion of the state. Some feel that this is a variety of white ash rather than a separate species. Commercially the lumber is marketed in the lumber trade with white ash.

Leaves are odd-pinnate with seven to 11 ovate to oval-shaped leaflets. Leaflets are 31/2—6 inches (9—15 cm) long. Leaflets are rounded at the base and sharply pointed at the tip. The leaflets are often falcate and have entire or finely toothed leaf margins. Foliage is dark green and smooth above and bluish-white, covered with fine hairs, beneath. The hairs are denser along the veins.

Biltmore ash can be easily separated from white ash by the twigs and stems that are densely covered with fine, soft hairs. Winter buds have one to two pairs of outer scales. The leaf scars are shallowly notched at the top. Twigs are circular in outline. The bark is noticeably furrowed on young trees. As the biltmore ash grows older, the furrows become deeper and the ridges become broader than the white ash.

Flowers are perfect or unisexual and open before the leaves are expanded in April or May. Fruit is a straight, 1-inch (25 mm) samara borne in clusters.

	European Ash

European Ash–Fraxinus excelsior

European ash is a smaller tree than the native American white ash and is quite similar to the black ash. As expected, this tree was introduced from Europe and western Asia. A number of cultivars have been introduced in the nursery trades in the United States and Europe. One cultivar has a simple leaf and is more commonly seen. They have not proven serviceable in U.S. landscapes and are rarely used. Lilac and ash borers are problems for this tree.

Leaves are opposite and pinnately compound. There are seven to 11 leaflets that are villous (long, soft, curved hairs) along the midrib. Leaflets are short-stalked or sessile with sharply toothed margins. Foliage is deep green above and lighter green beneath.

Winter buds have one to two pairs of outer scales and are black. Branches are dull gray to dark brownish. Leaf scars are more vertically elliptic than half-round. The first pair of side buds is usually below the terminal bud.

Flowers are perfect or unisexual. Flowers are borne as the foliage begins to emerge in April or May. Fruit is a samara.

Black Ash–Fraxinus nigra

	Black Ash

Black ash is smaller than the green ash or the white ash and has a more northerly distribution. Since it is a swamp species, it grows naturally in wet places. It is common in northern and southwestern Ohio, becoming rare in southeastern Ohio. Originally in the Black Swamp area of northwestern Ohio, black ash was prominently associated with cottonwood, American elm, soft maple, bur oak, and swamp white oak. The bark is gray and scaly and crumbles when rubbed with the palm of the hand. In dense stands, the tree is from 70—90 feet tall and 10—12 inches in diameter. Open-grown trees are half the height of woodland trees.

Leaves are opposite and odd-pinnately compound. The leaves are dark green and smooth above, and lighter beneath. There are seven to 11 leaflets that are rusty-woolly along the midrib. The leaflets are sessile. Leaf margins have small teeth.

Winter buds have one to two pairs of outer scales. Leaf scars are more vertically elliptic than half-round. The first pair of side buds is usually below the terminal bud. Buds are dark brown, almost black, and are narrower and more pointed than those of the white ash.

Flowers are perfect or unisexual. The fruit is a single key or samara and shaped like a canoe paddle. The seed is almost entirely surrounded by a wing. The end of the wing may be rounded or slightly notched.

The wood is light brown in color and lighter than the white ash, but not as strong. The wood has a decided grain which makes it suitable for furniture and interior finish. The Indians found that by pounding the wood of young stems, they could separate it into layers. The layers were used for baskets. Black ash wood is used for butter tubs, splint boxes, cabinet making, and veneers for baskets.

Green Ash–Fraxinus pennsylvanica

Green ash is smaller than white ash and usually does not exceed 60 feet. The tree has a shorter trunk and a rounded, open head. The green ash is found along the streams in all but extremely hilly sections of the state. This tree has spreading branches, an irregular growth habit, and a trunk diameter up to 2 feet. Two varieties are known. The variety subintegerrima (green ash) is characterized by glabrous branches and a more easterly range. The variety lanceolata (red ash) has pubescent branches and leaf veins, and a more northerly and westerly range.

Green Ash

The leaves are opposite one another on the stem and are odd-pinnately compound with a total length of 10—12 inches (25—301/2 cm). There are five to nine stalked leaflets that are lanceolate and not falcate. Foliage is dark to light green. Leaflets usually have toothed margins and may be glabrous or pubescent beneath. Fall color is a clear yellow.

The mature bark is 1/2 inch (13 mm) or more thick, brown tinged with red, and slightly furrowed or ridged. Twigs and leaf stems may or may not be pubescent. The leaf scar is half-round and normally straight across the top. Winter buds have one to two pairs of outer scales. The twigs are round and ashy gray, marked by pale lenticels and rusty bud-scales.

The flowers are small with the male and female flowers occurring on different trees. Flowers open just prior to leaf expansion in April or May. The fruit is flat, winged, 1—21/2 inches (21/2—6 cm) long, and 1/4—1/3 inches (6—8 mm) wide. The winged portion of the samara extends down past the middle of the seed-bearing portion. The wing is sometimes square or slightly notched at the outer end.

There are a number of named cultivars that are available in the nursery trade. Most green ashes are selected for yellow fall color, male flowers that do not produce fruit, and environmental-tolerance when established. 'Summit' has an oval habit until it reaches 10 inches (25 cm) in trunk diameter. 'Patmore' is distinguished by its cold-tolerance. Green ash must be sprayed when planted in the landscape for one to two years to control ash and lilac borers.

The wood is heavy, hard, rather strong, brittle, and coarse-grained. The light brown heartwood has a rather broad layer of lighter sapwood. The wood is similar to that of the white ash, though not as desirable, and is generally used for the same purposes.

Blue Ash–Fraxinus quadrangulata

The blue ash is confined to the limestone soils of western Ohio. It is seldom found in the eastern part of the state. The blue ash ranges from southern Ontario, Canada, to Iowa and south to northern Alabama and Arkansas. The blue ash becomes a large tree, 100 feet in height with a trunk 3 feet in diameter. Only one cultivar is in the nursery trade, and it is very uncommon. This tree's alkaline soil tolerance has not been exploited by our urban communities.

The leaves are opposite, and odd-pinnately compound with a total length of 8—12 inches (20—301/2 cm). Leaves have seven to 11 short-stalked leaflets. Leaflets are 2—5 inches (5—13 cm) long and 1—2 inches (21/2—5 cm) wide and are more lanceolate in outline than the white ash. Leaflets are acute-tipped and coarsely toothed. The leaves are thick, firm, smooth, yellowish-green above, and paler beneath. The veins, mid ribs, and leaflet stalks are permanently pubescent.

The young twigs afford the most characteristic feature of this species, as they are usually square, sometimes winged, or four-ridged between the leaf bases. This makes it the easiest to recognize of all the native ash trees. Twigs are glabrous. Winter buds have one to two pairs of outer bud scales. The mature bark is 1/2—2/3 inches (13—17 mm) thick, light grayish tinged with red, and irregularly divided into large, platelike scales. Macerating the inner bark in water yields the blue dye that gives this tree its name.

The flowers are without petals and appear in clusters when the buds begin to expand. Flowers are perfect or bisexual, thus the blue ash cannot be selected for fruitless trees. The fruit is flattened, oblong, 1—2 inches (21/2—5 cm) long, and less than 1/2 inch (13 mm) wide. The wings of the samara are usually notched at the outer end.

The wood is heavy, hard, and close-grained. The wood is light yellow, streaked with brown, and has a very broad zone of lighter sapwood. It is not distinguished commercially from the wood of other ash trees.

Blue Ash

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