American Mountain Ash

Basic Information
Tree ID: 
Genus and species: 
Located near Marsh Botanic Gardens, this fine specimen of a tree is a rewarding sight to the brave souls who trek up Prospect Street. Commonly known as rowan trees, American mountain ash are popular ornamentals in gardens and are widely used as street trees. In the spring and summer months they produce showy white flowers followed in the fall by orange berries that feed several species of birds and small mammals. Additionally, American mountain ash are the preferred snack of moose who feed on its foliage, twigs, and bark. Fear not, however, as this particular tree, nestled safely in New Haven, is not subjected to the ravages of wandering moose.
Sandra Mendiola
Collected Data
Tree shape: 
Date of tree entry: 
6.78 m
There are too many multiple trunks to accurately measure the DBH, so this is just an estimate
The bark is light gray and smooth. Young American mountain ash tend to be smooth while older trees develop cracks and scaly patches with age.
Twigs & branches
This particular tree is highly branched. Its twigs are somewhat darker than the main branches of the tree and have downy, dark red winter buds.
The American mountain ash is a decidious perennial with alternate, pinnately compound leaves. Each leaf is serrated and has a lanceolate shape. In the spring and summer, the leaves are a dark yellow-green and in the winter they turn varying shades of yellow and red.
Reproductive Structures
The showy white flowers produced in the late spring and early summer make the American mountain ash a great ornamental tree. The flowers grow in clusters and individual flowers are rather small (only 1/8 inch across). The flowers of the American mountain ash are perfect, have 5 petals, an inferior ovary, and several stamens.
The fleshy, bright red to orange berries produced by the American mountain ash are a favorite treat of many bird species. They are usually present during the fall and last through much of the winter making them great sources of food for birds.
  • Spring
  • Summer
  • Fall
  • Winter
Natural range of distribution: 
Alpine or subalpine zones of mid-elevations. Native New England states include: Connecticut, Maine, Massachusetts, New Hampshire, and Vermont.
Origin, history, and uses: 

The American Mountain Ash has long been known as the Rowan tree, which is prominent in mythology and folklore. In European folklore it was thought to provide protection against evil and was sometimes called the “wayfarer’s tree.” American settlers in the 18th century thought the American mountain ash was a powerful tool for exercising witches and referred to it as “Witchwood.” The berries and bark of the American mountain ash were also used extensively by Native Americans for medicinal purposes. Uses included: teas for colds, digestion aids, painkillers, and emetics.

The American mountain ash is not well adapted to warmer climates and generally does not do well in areas with insufficient moisture. It is known to be slow growing and to prefer full exposure to the sun. In the wild the American mountain ash is usually short-lived due to mildew, fire bilght, excessive browsing, and disease carrying insects. In cultivation, however, the species does well, especially in the Northern part of its range. The phenology is variable depending on the locality but in the Northeast the trees tend to flower in May through June and fruit in August (but keep their berries throughout fall and winter).
Other information of interest: 

The American Mountain Ash is not a true ash. Although its leaves bear a superficial similarity to the compound leaves of ashes, American Mountain Ashes are actually part of the rose family. 

The American Mountain Ash is also one of very few trees that keeps its berries through the winter months.

The berries of this tree have a five pointed star at their base. This is one of the main reasons that they were thought to be such powerful symbols of protection. 

Media and Arts

Here we behold the Rowan

In New Haven it has been growin’

It’s a deciduous tree

And I think we all can agree

It’s an angiosperm not a protozoan.