14 Types of Ash Tree: Pictures, Facts and Natural Beauty (2024)

If you are an admirer of trees, then you’ve likely noticed the attractive ash tree, whether or not you know it by name. I spent years driving by the same strikingly colored street tree each fall before I learned exactly to which species it belonged.

It was a beautiful young white ash (Fraxinus americana), the ‘Autumn Purple’ cultivar, lit up gold from the inside like a torch with dark maroon leaves in its outermost layer, an unparalleled fall beauty.

In autumn, few trees can compare to the ash tree’s flashy displays of gold, maroon, or deep purple, colors that can sometimes be found all on the same tree in a stunning layer of color. You’ll know one when you see it! Truly unforgettable.

This spectacular tree is facing an ecological crisis and needs our care and attention. In the folklore of several countries, treating the ash tree with reverence and respect is associated with good luck. Let’s take a reverent look at this majestic giant of the forest.

Ash Trees Facts

Ash trees are in the Fraxinus genus within the Oleaceae family. Distant relatives of the ash within the Oleaceae family include lilac, forsythia, olive, jasmine, and fringetree. Over 60 varieties of Fraxinus lend their beauty, strength, and protection to the towns and woodlands of our world.

The ash is an important player in the forest, providing both food and a habitat for many animal species. Its tall stature shields the understory, protecting the growth of smaller trees. The flowers of the tree support a wide array of pollinators.

This tree species possesses inestimable value, both for its cultural significance and ecological importance as a keystone species, and some of its varieties are already listed as critically endangered. The ongoing loss of ash trees is producing a cascading effect on the ecology of our woodlands.

Not only is the ash tree of significant importance to the ecology of forests on multiple continents, nourishing and supporting the biodiversity of woodlots to wildernesses, it is also rooted in the mythology of many different peoples.

Ash Trees Around The World

Several cultures have the concept of the Great Cosmic Tree woven into their fabric from their earliest days, and the motif may have originated from Eurasian shamanic traditions. To the Celts and the Norse, the mighty ash symbolized the tree that linked our world with the otherworldly.

The common threads that bind these tales together across many lands are inspired by massive specimens, large enough to house the whole of the cosmos. One look at some of the oldest surviving ash trees and you can easily see how these majestic giants seem to hold heaven in their canopies.

Ash Trees Are Vulnerable to Disease

In ancient times, the fate of our world was viewed as linked to the health of the great world tree, a connection that appears more vital by the day as we realize how crucial these vulnerable forest dwellers are to the health of the planet as a whole.

Among the antagonists of the world’s ash population are types of fungi, such as verticillium wilt, anthracnose, and hymenoscyphus fraxineus, or ash dieback. In the United States and Canada, the ash population is besieged by the invasive emerald ash borer (EAB), a beautiful but deadly beetle from Asia.

The Emerald Ash Borer Devours Ash Trees

The greatest threat to the ash is the emerald ash borer (EAB). Like many villainous characters, the voracious emerald ash borer is a real beauty. It shimmers, jewel-like, glittering in the sunlight, but under that gorgeous coat of shiny green is the doom of the North American ash population.

The EAB is a devouring insect that has nearly decimated the US ash population in less than a decade. Spreading from tree to tree each year like a living wildfire, the insect represents the most destructive infestation ever observed in North America.

Ash Trees Fight Back Against Environmental Threats

A variety of interventions are being used to attempt to save the ash, and hopefully bring the susceptible varieties back from the brink of extinction.

• Pesticides. Individual trees respond well to the timely application of pesticides, and research into their long term effectiveness is ongoing.

• Biocontrol. The biological control management strategy involves introducing types of wasps that may stop the spread of the EAB. It will be years before we know whether or not this biocontrol approach will halt the swathe of destruction, but promising results have been observed at the experimental site in Michigan.

• Genetic research. While the ash trees in Asian countries are resistant to the EAB, the species in the US do not contain the genetic building blocks to resist the devouring horde of insects. Genetic research and breeding programs are a promising direction of research.

• Seed banks. In an effort to conserve genetic material for future propagation, ash tree seeds are collected and stored, waiting for the day when the EAB is no longer a threat.

These trees need our care and awareness now more than ever. If knowledge is power, there may yet be hope for the Fraxinus species as a whole. Learning all we can about this beautiful tree, we may be able to save it and, by extension, ourselves.

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Ash Trees and Urban Street Design

From street trees to towering woodland specimens, ash trees can be found spread across North America, Europe, and Asia. There are 18 species native to North America, ranging from the Southwestern US across to northern Florida, and spreading over the Eastern US and up into Canada.

The ash tolerates a wide variety of environmental conditions, making it one of the more commonly found trees. All ash trees are sun-loving, although a few varieties can handle some shade. They generally prefer a wet environment with a few notable exceptions which grow in drier climates.

Ash Tree Identification: The Ash Basics

There are a number of distinguishing characteristics common to all ash trees:

• Opposing branches. They have opposing buds and branches, which means they grow directly across from each other. Very few species of trees grow in this manner, so knowing to look for these “mate” branches can really help with identification!

• Compound leaves. The leaves of the ash are called compound leaves because they are made of 5-9 leaflets stemming from a single bud. Most trees have single leaves arising from each single bud.

• Oar-shaped seeds. The ash tree fruits with flair, having clusters of unique winged seeds that fly far on the wind. These elongated seeds are relatively easy to spot, growing in pendant clusters from the branches.

• Diamond-pattern bark. Mature trees have a distinct diamond pattern in their bark which grows more pronounced over time. Young trees begin with fairly smooth bark, but the diamond pattern is unmistakable in older specimens.

There are a few trees that resemble the ash, and they may even have the word “ash” in their common names, however, they are not true ash trees. For example, elm, boxelder, walnut, and hickory are visually similar to ash trees.

The most well-known of these is the mountain ash, or rowan tree, Sorbus americana, with its showy red-orange rowan berries and froth of white flowers in May. The rowan is actually in the rose family.

Samaras: The Seeds of an Ash Trees

Of special note are the winged achenes, or seeds, of the tree. These lovely clusters of fluted seeds are also known as samaras, and are a type of botanical fruit found only on female trees. Some trees hold this fringe of seeds through the seasons, adding winter interest to otherwise bare branches.

The samaras we are most familiar with are sugar maple “helicopters,” which delight many children when they spiral to the ground late in the fall season. The elm tree also produces samaras, dropping their seeds to the earth in a rain of flat packets shaped like oval plates or discs.

The shape of these seeds, with their elongated fibrous wings, carry the seeds away from the base of the tree toward sunnier, more hospitable ground. They also send the fruit of the tree far from those animals that would feed on the fallen seeds, such as mice, squirrels, songbirds, ducks and other birds.

Ash Offers Woodworkers Quality Materials

The wood of the ash is dense, yet lightweight. The strength of ash wood combined with its shock resistance makes it an ideal material for use in sports equipment such as baseball bats, hockey sticks and boating oars.

These same qualities make the ash a top choice for the handles of handheld tools. It is a flexible hardwood, which is rare, and is often used in cabinetry, flooring, and household furnishings. The color of ash ranges from white to a light or medium brown, adding an aesthetic element to home decor.

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The 14 Different Types of Ash Trees

Local Color

We are fortunate to have 18 varieties of ash tree native to the United States. They are perhaps best known for their autumn foliage, producing hues that range from vibrant gold to deep purple. The most common varieties include the following five species:

1. White ash (Fraxinus americana)

This beautiful North American native tree, also known as Biltmore ash, begins growing in a pyramidal shape that rounds into a full crown with age. It is often cultivated as a shade tree. This largest of the native ash varieties is often found in parks, or dominating the woodland canopy with its towering crown.

Growing at a rate of 13”- 24” annually, it will reach a height of 50-80’ at maturity, with a crown 40-50’ wide. It bears compound leaves 8–15″ in length, each with 5–9 dark green leaflets.

Native area: Eastern North America

USDA growing zones: 3 to 9

Height: 50 to 80 feet (15 – 24 meters)

2. Green ash (Fraxinus pennsylvanica)

This highly adaptable tree grows in a wide variety of conditions, even tolerating salt runoff and pollution. A great choice for urban locales, it’s often used as a street tree. Other common names for it are red ash and water ash, and swamp ash. It bears leaves with 5-9 toothed leaflets, usually numbering seven, which are glossy green with pale undersides.

Native area: Eastern and northern North America

USDA growing zones: 3 to 9

Height: 50 to 70 feet (15 – 21 meters)

3. Black ash (Fraxinus nigra)

The Wabanaki used the pliable black ash to weave baskets, and the tree figures prominently in their creation story. This type loves wet conditions and can be found in swamps and wetlands. It has 11 leaflets per leaf, and the bark can grow soft and spongy as the tree matures.

Native area: Eastern Canada and the northeastern U.S.

USDA growing zones: 2 to 6

Height: 40 to 60 feet (12 – 18 meters)

4. Blue ash (Fraxinus quadrangulata)

The telltale square shape observed in the young tree branches makes this an easy species to identify. The inner bark turns blue when exposed to the air, hence the name. The reactive gelatinous inner layer was used by pioneers as a dye for fabrics.

Leaves are composed of 7-11 leaflets. This is one of the rare specimens that tolerates dry locations, though it expresses the characteristic flexibility of many ash cultivars, enjoying both wet and dry conditions.

While genetically resistant to the emerald ash borer, an insect devastating the population of ash trees across the US, it is very susceptible to the lilac borer. You may recall that ash trees and lilacs share a common branch of the family tree.

Native Area: Midwestern U.S.

USDA Growing Zones: 4 to 7

Height: 50 to 70 feet (15 – 21 meters)

5. California ash (Fraxinus dipetala)

Common names for this variety are the foothill ash or two-petal ash. Unlike its giant native fellows, it is often labeled a shrub, reaching heights of a mere 25 feet (8 meters). This smaller tree has other characteristics which differentiate it from our other ash trees, such as its 3-9 rounded leaflets with serrated edges, and its clusters of distinctive dainty two-petaled flowers. This is an ideal choice for drier climates.

Native area: California, Arizona, Utah, Nevada, Baja California

USDA zones: 7 to 9

Height: Up to 20 feet (6 meters)

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Ash Tree Varieties

Other than these commonly seen varieties, there are a number of noteworthy ash trees with varying characteristics found throughout the US. Out of the 60 or so varieties of ash, here’s a sampling of a few:

6. Pumpkin Ash (Fraxinus profunda)

This ash derives its name from the bulbous growth of the base of the tree, especially pronounced when found growing in wetter soil. The pumpkin ash, or red ash, is most frequently seen growing in the wild rather than as a chosen cultivar.

It’s 7-9 leaflets take on bronze or maroon hues in the fall. It also features beautiful red-tipped samaras, the seeds of the tree.

Native area: Eastern North America

USDA growing zones: 5 to 9

Height: 60 to 80 feet (18 – 24 meters)

7. California ash (Fraxinus dipetala)

Common names for this variety are the foothill ash or two-petal ash. Unlike its giant native fellows, it is often labeled a shrub, reaching heights of a mere 25 feet (8 meters). This smaller tree has other characteristics which differentiate it from our other ash trees, such as its 3-9 rounded leaflets with serrated edges, and its clusters of distinctive dainty two-petaled flowers. This is an ideal choice for drier climates.

Native area: California, Arizona, Utah, Nevada, Baja California

USDA zones: 7 to 9

Height: Up to 20 feet (6 meters)

8. Velvet Ash (Fraxinus velutina)

Named for the downy velvet texture of its new shoots, this tree is also known as the Dixie white ash, Modesto ash or Arizona ash. This fast growing tree is a mountain native, and smaller than the giant ashes in the family. It is frequently cultivated in urban settings, tolerating drought conditions, compacted soil, and the pollutants of life in the city.

The foliage of the velvet ash is finely serrated, having 5-7 leaflets per compound leaf.

Native area: Southwestern North America

USDA Growing zones: 7 to 10

Height: 30 to 50 feet (9 – 15 meters)

9. Carolina Ash (Fraxinus caroliana)

As the name suggests, this variety can be found in the Carolinas, and further south throughout the subtropical US. Sometimes called pop ash or water ash, it grows in swamplands or near river banks where it frequently leans out over the waters. Unlike most ash varieties, it can tolerate some shade.

The seeds have a broader wing, often with a rosy, wine-stained hue. The bark can be scaly or splotchy, and lichens may be present. The base of the tree may be slightly engorged as well. The 5-7 leaflets are glossy on top and pale underneath with a serrated edge.

Native area: Cuba, subtropical southern U.S.

USDA growing zones: 7 to 9

Height: 30 to 40 feet (9 – 12 meters)

10. Gregg’s Ash (Fraxinus greggii)

This scrubby little specimen, also called littleleaf ash, dogleg ash, or Mexican ash, grows well in inhospitable spaces, such as rocky limestone slopes, dry creek beds and washes, and arroyos and canyons. It is often cultivated as a container plant. It’s shrubby growth may be encouraged to grow into a small multi-trunk tree.

This variety gives the appearance of being an evergreen, as the new leaves emerge in the spring just as the old leaves drop. The smaller, bright green compound leaves hold 3-11 leaflets and have a toothed margin.

Native area: Arizona, New Mexico, and Texas

USDA growing zones: 7 to 10

Height: 15 to 20 feet (5 – 6 meters)

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Worldwide Distribution of Ash Trees

We’ve looked at some of the species that populate North America, and the ash tree can also be found scattered over Asia and Europe. From urban streets to forest canopies, the ash tree contributes to the biodiversity of several continents. Here are a few notable specimens that may be found abroad:

11. Manchurian Ash (Fraxinus mandschurica)

Native to northeast Asia, the Manchurian ash can also be found growing in parts of North America. It is of particular interest due to its resistance to the emerald ash borer. Experimental research in the viability of cross pollinating resistant species is one of the ways we are trying to push back the bar of looming extinction, and the Manchurian ash has been used in these experiments.

Though it is prized by landscapers for its shapely oval form and long-lasting chrome yellow autumn foliage, it is not without its own vulnerabilities. While resistant to the EAB, it is susceptible to a fungus called anthracnose, a disease that weakens the structure of the tree over time. It has also been known to exhibit a mutated growth pattern known as fasciation.

Young trees have smooth gray bark that develops fissuring with age, characteristic of the ash. At one year old, twigs are golden in color. The leaflets have serrated edges with 9-11 per compound leaf. The Mancana is an attractive and popular cultivar. It has the added benefit of being a male tree, so no messy fallen seeds to clean up.

Native area: Eastern Asia

USDA growing zones: 3 to 6

Height: 40 to 50 feet (12 – 15 meters)

12. Manna Ash (Fraxinus ornus)

The sugary sap from the tree gives rise to its name as its sweet sap was compared to the Biblical manna. Both the sugar alcohol mannitol and the sugar mannose are derived from the sap of the tree. It’s other common name, flowering ash, is a nod to its fragrant display of creamy white flowers in May.

Unlike other it’s rough-barked relatives, the smooth gray bark of this ash tree remains smooth even in full maturity. Groups of 5-9 leaflets with serrated edges range from yellow to purple in the fall.

Native area: Southern Europe and southwestern Asia

USDA growing zones: 6 to 9

Height: 40 to 50 feet tall (12 – 15 meters)

13. Narrow-leaved Ash (Fraxinus angustifolia)

Also known as Caucasian or desert ash, this variety tolerates drought and wind but must have full sun. It can grow in acidic or very alkaline soil and dry, rocky environments. The claret ash, or Raywood cultivar, is a favorite, producing a striking shade of purple in the fall.

Cultivars display 3-13 narrow leaflets per compound leaf, depending on the variety. Pale brown buds contrast with the black buds of the Fraxinus excelsior, making it easier to tell the difference between these two similar trees.

Native area: Southwest Asia, southern and central Europe, and northwest Africa

USDA growing zones: 5 to 8

Height: 50 to 80 feet (15 – 24 meters)

14. European Ash (Fraxinus excelsior)

Found throughout Europe, this tree is widely grown with many different cultivars from towering 200 year old giants of the forest to weeping types that bow to the ground.

The species name, excelsior, is from the Latin for taller or higher.

The 7-11 leaflets can turn yellow in the fall, but will drop while still green if there is an early frost. Their most distinguishing feature is their black buds, a sharp difference from the brown color of most ash types. The clusters of samsaras are frequently referred to as “winged keys,” appearing like a bundle of keys hanging on a key ring. While susceptible to the EAB, the fungal disease known as ash dieback is currently a greater concern, particularly in the UK.

Native area: Europe and southwestern Asia

USDA growing zones: 5 to 8

Height: 60 to 80 feet (18 – 24 meters)

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Saving Ash Trees for Urban Forests

The fate of the ash is uncertain, yet there is still time to enjoy these beautiful trees as we search for solutions. Simply by enlarging your knowledge of the ash and the challenges it faces puts you in a position to be part of those solutions.

Now that you’re acquainted with this gentle giant of the forest, go and find one near you! Stand under the glowing canopy and get to know it a little better. Enjoy the company of the mature trees that remain. For many of them, their days are numbered. Let them inspire you to save the ones we can, together.