Ash Tree Guide: What Is It + 15 Common Species of Ash Trees (2024)

The ash tree belongs to the olive (Oleaceae) family of woody plants and is classified under the Fraxinus genus. It has between 44 to 66 species of large to medium trees, some of which are subtropical and evergreen. The genus is widely distributed across Europe, Asia, Africa, and North America.

They were previously the most widely planted urban tree in the United States and are frequently utilized as shade, lawn, and street trees.

You can identify ashes by searching for trees with opposite branching and compound leaves composed of clusters of 5-11 leaflets. Ash trees often have distinctive bark that differs depending on the species.

Ashes are dioecious trees, which means that each tree only has male or female parts. If you don’t want the fruit/seed mess, you can choose male trees.

Ash tree fruits are called samaras and resemble the winged seeds of maple trees with an oar shape. They usually occur in clusters on trees and hang there until late fall to early winter.

In folklore and ancient Celtic, Greek, Chinese, and Norse religions, this tree represents protection, healing, balance, and rebirth.

Is the Ash Tree Endangered?

Due to ash tree disease and the emerald ash borer beetle, the once-abundant ash tree genus is in danger of going extinct.

Unfortunately, the most valuable and common tree in North America is being wiped out by an invasive beetle known as the Emerald Ash Borer beetle, according to the most recent update of the IUCN Red List of Threatened Species.

These trees are an important component of North American woodlands. They support crucial pollinator species like moths and butterflies and provide food and habitat for birds, insects, and squirrels. 80% of trees will be severely impacted by the decline of these species, which will also alter the makeup of both urban and natural forests.

The devastating Emerald Ash Borer beetle is devouring tens of millions of ash trees left behind by the ash tree disease, worsening an already troublesome situation.

Unfortunately, it’s difficult to predict the extent of the beetle’s infestation in the future due to its current suitability for very cold climates as a result of global warming.

Photo Credit: Dreamstime.

How Does the Emerald Ash Borer Damage Ash Trees?

Millions of ash trees have been killed by the emerald ash borer, a destructive pest that has affected at least 35 states.

Although the adult Emerald Ash Borer beetle (Agrilus planipennis) doesn’t do much harm, when its eggs hatch and the larvae begin to feed on the inner tissues of the tree, they impede the tree’s ability to transmit water and nutrients and eventually cause the tree to die. Insecticides can be used to protect existing trees.

While many communities deal with the emerald ash borer problem by destroying both diseased and healthy trees to slow the spread of the beetle, some homeowners try to save or protect individual trees by applying systemic insecticides containing imidacloprid as soil drenches around the base of an ash tree.

How to Identify an Emerald Ash Borer Infestation on Ash Trees

To identify an infestation, look for these telltale signs:

• Dead branches on top of the tree
• Bark flecking in top branches. These can also be created by woodpeckers eating insects so rule that out as a possibility first.
• Cracks in barks caused by larvae digging beneath the bark.
• D-shape exit holes caused when adult beetles leave in late Spring

In order for a pesticide to be effective, it must be drenched yearly in the spring. Treatment works best if it starts before the tree becomes infected. Unfortunately, trees that have lost 50% or more of their canopy usually can’t be saved.

15 Species of Ash Trees

There are many different types and species of Ash trees in the United States and other countries around the world. Here are the 15 most common ones:

1. Black Ash (Fraxinus nigra)

• Botanical Name: Fraxinus nigra
• Common Names: Black ash, swamp ash, basket ash, brown ash, hoop ash, water ash
• Hardiness Zones: 3 – 6 (USDA)
• Sun Exposure: Full sun
• Soil Type: Well-draining, sandy, loamy
• Soil pH: Acidic to slightly alkaline
• Mature Size: 50 to 80 feet

Black ash is a great material for weaving because of its flexible wood structure. This ash tree can flourish in both chilly and wet locations. This tree attracts wildlife since birds and animals eat its seeds.

Deer and moose, which are native to eastern Canada and the northeastern United States, also enjoy chewing on the branches and leaves. As the tree matures, the thick gray bark develops fissures and scaly patches.

Each compound leaf group on this ash species contains seven to thirteen leaflets, and in the fall, the foliage turns yellow.

Due to the emerald ash borer’s severe damage to this species of ash, experts no longer recommend planting it.

2. White Ash (Fraxinus americana)

• Botanical Name: Fraxinus americana
• Common Names: White ash, Biltmore ash, Biltmore white ash
• Hardiness Zones: 3 – 9 (USDA)
• Sun Exposure: Full sun
• Soil Type: Rich, loamy, moist, well-draining
• Soil pH: Acidic to slightly alkaline
• Mature Size: 60 to 80 feet

White ash is another common ash tree in the eastern United States that has been severely impacted by the emerald ash borer.

This is the largest of the natural ash trees and is also known as Biltmore ash. As the tree grows older, its pyramidal shape gradually gives way to a perfectly rounded crown.

In older trees, its gray bark bears a distinctive pattern of diamond-shaped ridges. Its leaves are composed of clusters of five to nine leaflets that are whitish-green on the undersides and dark green on top. Its leaves turn purplish yellow in the fall.

3. Green Ash (Fraxinus pennsylvanica)

• Botanical Name: Fraxinus pennsylvanica
• Common Names: Green ash, red ash
• Hardiness Zones: 3 – 9 (USDA)
• Sun Exposure: Full sun
• Soil Type: Well-draining
• Soil pH: Acidic to slightly alkaline
• Mature Size: 50 to 70 feet

Green ash is one of the most common ashes in eastern and northern North America, and it is another species that has been seriously harmed by the emerald ash borer.

It can grow in various soil conditions and is particularly tolerant of urban areas’ pollutants and salt. Red ash, swamp ash, and water ash are some of the other common names of this ash tree specie.

The gray-brown bark has a distinctive pattern that resembles a diamond. Five to nine leaflets make up the medium-green leaves, which in the fall change color to various hues of yellow.

Although the green ash tree is frequently planted as a shade tree, they are not recommended in regions with emerald ash borer issues.

4. Blue Ash (Fraxinum quadrangulata)

• Botanical Name: Fraxinus quadragulata
• Common Name: Blue ash
• Hardiness Zones: 4 – 7 (USDA)
• Sun Exposure: Full sun
• Soil Type: Moist, well-drained, loamy
• Soil pH: Acidic to slightly alkaline
• Mature Size: 50 to 75 feet

The name “blue ash” comes from the way the inner bark changes color in the air. This species is native to the midwestern United States and was used to manufacture blue dye. The square shape of young shoots is a distinguishing feature of this species.

The gray bark of mature trees develops into irregular plates. The leaves grow in clusters of seven to eleven leaflets and become dull yellow and gray in the fall. Even though it’s regarded as one of the best ashes for dry, arid areas, it also surprisingly grows well in medium-wet environments.

According to reports, blue ash, which is typically used as a shade or street tree, has a significantly higher survival rate in regions where emerald ash borer infestations are prevalent. This might be because of some innate genetic resistance. It is not as resilient as other Asian species, though.

5. California Ash (Fraxinus dipetala)

• Botanical Name: Fraxinus dipetala
• Common Names:California ash, two-petal ash
• Hardiness Zones: 7 – 9 (USDA)
• Sun Exposure: Full sun
• Soil Type: Well-drained
• Soil pH: Acidic to slightly alkaline
• Mature Size: Up to 20 feet

The California ash, also known as two-petal ash, is a shrub or small tree that looks very different from other ashes. It’s native to Arizona, California, Utah, and Nevada. The leaves, which form clusters of three to nine leaflets, have rounded ends and serrated edges.

It’s also known as the two-petal ash thanks to its white flowers that feature two petals and hang in fragrant clusters. Due to its extremely low water requirements, this plant is ideal for drought conditions.

California ash has not yet been impacted by the emerald ash borer in its natural habitat. However, there is evidence that the beetle has gone as far as Colorado in the west and it will probably make it to the West Coast.

6. Carolina Ash (Fraxinus caroliniana)

• Botanical Name: Fraxinus caroliniana
• Common Names:Carolina ash
• Hardiness Zones: 7 – 9 (USDA)
• Sun Exposure: Full sun to partial
• Soil Type: Moist soil
• Soil pH: Acidic to neutral
• Mature Size: 30 – 40 feet

Carolina ash is frequently seen in swamps and marshes since it thrives in moist soil. It is native to South Carolina, North Carolina, and other nearby marshy states. Other popular names for this tree include pop ash, water ash, swamp ash, and Florida ash.

This unusual ash tree is ideal for stabilizing marsh environments since it thrives in the shade. Typical leaf clusters on the tree include five to seven leaflets each.

Although the Emerald ash borer has not yet arrived in the Carolina ash’s native habitat, experts warn that its arrival is possible.

7. European Ash (Fraxinus excelsior)

• Botanical Name: Fraxinus excelsior
• Common Names:European ash, common ash
• Hardiness Zones: 5 – 8 (USDA)
• Sun Exposure: Full sun
• Soil Type: Moist, well-draining
• Soil pH: Acidic to slightly alkaline
• Mature Size: 60 – 80 feet

European ash is as widespread as its name implies, and for this reason, it’s also referred to as common ash. Unlike most ashes, this tree typically grows to be wider than tall. Look for black buds to distinguish them from other ashes, which typically have brown buds.

European ash leaves have seven to thirteen leaflets each. The natural species usually drop their leaves while they are still green, unlike other cultivars that turn yellow in the fall.

Compared to black, green, and white ash, European ash is considered less attractive to the emerald ash borer, yet it is still vulnerable.

8. Gregg’s Ash (Fraxinus greggii)

• Botanical Name: Fraxinus greggii
• Common Names:Gregg’s ash, Mexican ash, dogleg ash, tiny leaf ash
• Hardiness Zones: 7 – 10 (USDA)
• Sun Exposure: Full sun to partial
• Soil Type: Well-drained
• Soil pH: Neutral to alkaline
• Mature Size: 15 – 20 feet

Gregg’s ash is a huge shrub native to Arizona, New Mexico, and Texas that can be trained to grow into a small tree.

Once grown, it can withstand drought and be used as a container specimen. Compared to other ash tree species, this one has leaves that grow in clusters of three to eleven leaflets.

The limbs are relatively slender, and the bark is smooth and gray. Other names for this plant include tiny leaf ash, Mexican ash, and dogleg ash.

This is one of the few ashes that will grow in partial shade. This tree’s native range has not yet been damaged by the emerald ash borer, although it might in the future.

9. Manna Ash (Fraxinus ornus)

• Botanical Name: Fraxinus ornus
• Common Names:Manna ash, flowering ash
• Hardiness Zones: 6 – 9 (USDA)
• Sun Exposure: Full sun
• Soil Type: Sandy, loamy, clay
• Soil pH: Mildy acidic to mildly alkaline
• Mature Size: 40 – 50 feet

Thanks to its sweet sap extract, manna ash is named after the biblical food. It is native to southern Europe and southwestern Asia. This sap contains the sugar alcohol mannitol and the sugar mannose.

This plant, sometimes known as flowering ash, has one of the most attractive flower displays of all the ashes, which appear in May. Even in elderly trees, the dark-gray bark on this tree is smooth.

The leaves have five to nine leaflets in each bundle and have sharply serrated edges. In the fall, they turn yellow-purple.

This Asian type of ash tree may be more resistant to the emerald ash borer than other non-native ash trees, although the specific reason for this is not yet known.

10. Narrow Leaf Ash (Fraxinus angustifolia)

• Botanical Name: Fraxinus ornus
• Common Names:Narrow-leaf ash, desert ash
• Hardiness Zones: 5 – 8 (USDA)
• Sun Exposure: Full sun
• Soil Type: All types of soil
• Soil pH: Mildy acidic to alkaline
• Mature Size: 50 – 80 feet

The narrow-leaf ash is a medium- to large-sized tree that thrives in urban areas and acidic soil. It is referred to as desert ash and grows naturally in Europe, Africa, and Asia. On young trees, the bark is smooth and pale gray, but as the tree becomes older, the bark becomes square-cracked and knobby.

The most widespread cultivar, ‘Raywood,’ is often known as claret ash, after the gorgeous purple color it produces in the fall.

The small leaf ash tree is remarkably similar to the related Fraxinus excelsior, but its buds are pale brown instead of black. The leaves are composed of three to thirteen leaflets and are rather thin.

This is another non-North American ash and may be more resilient to emerald ash borers’ damage.

11. Pumpkin Ash (Fraxinus profunda)

• Botanical Name: Fraxinus profunda
• Common Names:Pumpkin ash, swelled butt ash, red ash
• Hardiness Zones: 5 – 9 (USDA)
• Sun Exposure: Full sun
• Soil Type: Moist, wet soil
• Soil pH: Neutral
• Mature Size: 60 – 80 feet

Pumpkin ash gets its name from the fact that the base of the trunk grows engorged and can resemble a pumpkin, especially in damp soils. Swelled butt ash and red ash are the other common names for this ash tree species. This tree has a thick trunk and thick, gray, fissured bark that is native to eastern North America.

The clusters of seven to nine leaflets that make up the leaves turn golden to purplish-red in the fall. This tree is a common selection for sizable rain gardens since it prefers damp soil. This ash tree is massive and requires a lot of area.

Experts now advise against growing it since it is one of the ash species that have been most severely impacted by the emerald ash borer.

12. Velvet Ash (Fraxinus velutina)

• Botanical Name: Fraxinus velutina
• Common Names:Velvet ash, Arizona ash, Modesto ash
• Hardiness Zones: 7 – 10 (USDA)
• Sun Exposure: Full sun
• Soil Type: Moist, wet soil
• Soil pH: Alkaline
• Mature Size: 20 – 50 feet

Velvet ash thrives on damp or alkaline soils and is drought-tolerant. If you require a tree that develops quickly, this is a good choice. This tree, also known as the Arizona or Modesto ash, is native to the Southwestern United States.

The shoots emerge with a velvety coating, and the bark is rough and fissured. Planting this ash is not recommended in some regions since the emerald ash borer has recently become a bigger problem for it.

13. Manchurian Ash (Fraxinus mandschurica)

• Botanical Name: Fraxinus mandschurica
• Common Names:Manchurian ash
• Hardiness Zones: 3 – 6 (USDA)
• Sun Exposure: Full sun
• Soil Type: Moist, well-draining
• Soil pH: Acidic to alkaline
• Mature Size: 40 – 50 feet

Thanks to its proven resistance to the emerald ash borer, Manchurian ash is becoming more and more popular as a landscape species. To create a species that can withstand the beetle assault, experiments are being conducted to cross this species with native North American ashes.

It is a sizable tree with broad compound leaves that can have up to 11 leaflets and turn a lovely yellow in the fall. As the tree ages, the smooth gray bark develops a few small fissures.

14. Shamel Ash Tree (Fraxinus uhdei)

• Botanical Name: Fraxinus uhdei
• Common Names:Shamel ash, tropical ash
• Hardiness Zones: 8 – 11 (USDA)
• Sun Exposure: Full to partial sun
• Soil Type: Any type of soil
• Soil pH: Highly acidic to alkaline
• Mature Size: Up to 80 feet

This ash tree species, often known as tropical ash, is native to Central America and Mexico. In the southwest United States, Mexico, and Hawaii, it is frequently planted as a street tree.

It has wide, semi-evergreen leaves, grows quickly, and reaches a height of 80 feet.

15. Oregon Ash Tree (Fraxinus latifolia)

• Botanical Name: Fraxinus latifolia
• Common Names:Oregon ash tree
• Hardiness Zones: 6 – 8 (USDA)
• Sun Exposure: Full to partial sun
• Soil Type: Rich, loamy, moist, well-draining
• Soil pH: Mildly acidic to mildly alkaline
• Mature Size: 60 – 80 feet

The Oregon ash tree is the Pacific Northwest’s sole native ash species.

It grows to a height of 60 to 80 feet when fully grown. Growing trees develop short, slender crowns with lengthy branches. It has a shallow, thickly fibrous, and widely dispersed root system.

Other Tree Guides from Planet Natural:

Banana Tree: How to Plant, Grow and Care for Banana Tree Plant