Good for More then Youth Artillery

As children, my friends and I were well acquainted with mountain ash trees. European Mountain Ash (Sorbus aucuparia) was ubiquitous to suburban home lots in the Northeast in the 1950’s, and the trees were readily recognized by their ferny leaves and clusters of flashy berries that also served as artillery.

European mountainash

Since that time, mountain ashes have fallen out of favor — and rightly so in many cases. Like our native white birch, European Mountain Ash is native to cool, moist habitats. When planted in sun-drenched backyards where summers are hot, sometimes droughty, they fall prey to borers and other ills. Those berries aren’t actually berries, but pome fruits like apples, to which mountain ashes are closely related and with which they share many of the same ills.

No reason to ignore the whole Sorbus genus, though; with good growing conditions and some choice of species or variety, Sorbus can thrive to provide four seasons of beauty, two of those seasons in spectacular style. In spring, branches come alive with drooping or upright clusters of creamy white blossoms, or, in the case of Kashmir Mountain Ash, pink blossoms.

At the other end of the growing season, autumn coaxes the most spectacular show, as the clusters of berries color up to, depending on the species and variety, fire-engine red, orange, pink, or white. Even species with white berries, such Kashmir Mountain Ash (S. cashmiriana), contribute to the show with the large size of their berries, each with a prominent red eye and fruit stalk.

Kashmir Mountain Ash

Autumn also brings fiery foliage, from yellow, to orange to an earthy combination of these hues.

Korean mountainash in autumn

To more readily grasp the full spectrum of Sorbus, with over a hundred species, it’s been split up into a half dozen or so botanical sections or subgenera. For garden purposes, it’s most convenient to consider separately those plants with pinnate (compound) leaves and those with simple leaves.

Rowans

European Mountain Ashes of my youth are representative of Sorbus having pinnate (compound) leaves. This group is also called rowans, from the Norse word rune, meaning mystic signs or writing, and reflecting the plants’ long history of use in staving off witches. “Rowantree and red threed/Put the witches to their speed” goes an old Scottish rhyme.

European mountain ash, flowers

European Mountain Ash (S. Aucuparia, Zone 2-5), also known as Quickbeam or simply as Rowan, is a fine ornamental tree where conditions are to its liking, namely, cool in summer. This tree has been cultivated for centuries in Northern Europe and is now naturalized in North America. Many varieties exist, from those with lacy with deeply jagged-edged leaflets to those with very upright form to those with copper-colored bark, to name a few variations.

American Mountain Ash (S. americana, Zone 2-7) is similar to its European cousin. Its growth habit is more bushy, and it’s perhaps more pest-resistant than its European counterpart. You’ll rarely find trees for sale but it does cheer up cold forests from Newfoundland to Manitoba, south down the Appalachian range to Georgia.

American mountain ash

The berries feed such birds as grouse, grosbeak, and cedar waxwings, while the fragrant bark provides sustenance to moose, leading to one of the tree’s other names, missey-moosey.

Let’s cross the Pacific Ocean to take a look at some Asian rowans. Like the previously mentioned Kashmir Mountain Ash, Vilmorin’s Rowan (S. vilmorinii, Zone 6) also has white fruits — eventually, going from rose red to pale pink before turning creamy white. This species has a shrubby growth habit and grows about 12 feet high.

Japanese Mountain Ash (S. commixta, Zone 6) is upright growing, reaching a height of thirty feet. Leaves unfold with a coppery hue, then turn a pleasant deep purple at the other end of the season, creating a perfect backdrop for the orange red fruits.

Whitebeams

With Whitebeams’ loose clusters of flowers and fruits and their simple leaves, their kinship to Rowans is not all that obvious. Though simple, the leaves are eye catching because their dense covering of down makes them appear almost white. Although well-known in Europe, Whitebeams have never caught on this side of the Atlantic.

As leaves unfold in spring from the fat buds of the Common Whitebeam (S. Aria), the tree might momentarily be mistaken for a magnolia in bloom. Later, with all leaves unfolded and only their undersides still downy white, the trees put on a glittery show as they flutter in breezes. This tree, often shrubby, grows to thirty-five feet and is adapted from Zones 4 to 6.

Common whitebeam

Another notable Whitebeam is the Swedish Whitebeam (S. intermedia, Zone 6) of northern Europe. This small, densely twigged, round-headed tree is well-known as an ornamental in Britain.

Almost twenty years ago at the Swarthmore College arboretum I happened upon an up and coming star among Whitebeams, Korean Mountain Ash (S. alnifolia). I had read that the fruit, though small, was a tasty nibble, so I ate a few — and they were. I also took home a few fruits for seed, planted them, and one seed has given rise to a 25 foot high tree.

Korean mountainash fruit

Edible Sorbus

Besides providing tasty treats to birds (aucuparia means “to catch birds,” because fowlers once used these fruits to trap birds), fruits of some Sorbus also are good food for you and me.

I happened upon fruits of the Service Tree (S. domestica, Zone 6) one day many years ago at another college arboretum, the Arnold Arboretum of Harvard University. (Not to be confused with “Service Trees” in the Amelanchier genus.) At my feet were a number of dropped, yellow fruits that resembled Bartlett pears — Lilliputian Bartlett pears only an inch or so long. Those that had softened were very good, and pear-like.

Sorbus domestica fruit

Wild Service Tree (S. torminalis, Zone 6), also known as Chequer Tree and native to Europe, north Africa, and Asia Minor, is best known for its majestic proportions and edible fruits. They are russet red, the size of smallish cherries, and were once made into drinks.

For fresh eating, let’s bite into a fruit of Yu’s Whitebeam (S. yuana, recently changed to Aria yuana), borne on a tree strongly resembling Korean Mountain Ash except for having larger fruits. The olive sized fruits are reputedly sweeter than pears, but with a flavor all their own; I’ll have to grow this one.

Sorbus also hybridizes with some other members in the Rose Family. Rarely known or grown, these intergeneric hybrids reflect influences of both parents. Among these hybrids are those with aronia (XSorbaronia), cotoneaster (XSorbocotoneaster), and amelanchier (XAmelosorbus).

My favorite intergeneric hybrid is that of Sorbus with Pyrus, pear. Twigs and the undersides of leaves of this tree (XSorbopyrus) are covered with a downy felt. As for the fruit, picture a small, golden yellow pear about two inches across and rounded so as to retain just a hint of pear-ness.

Sorbopyrus blossoming

The origin of one variety, Shipova, can be traced to sometime before 1610, in Europe. It made its way to America in the early part of the 20th century, and thence to my garden. 

The flavor or Shipova is similar to pear, its texture meatier — a perfect fruit to drop in your pocket for snacking during an autumn hike.