Holly & Mountain Ash: Berry Rich, Very Different

American mountain ash and American holly generally occupy separate ranges in North America. Their domains, however, converge in the Southern Appalachians, where the two trees exhibit an interesting duality along the mountain slopes.

Mountain ash is found along the highest peaks, while holly is abundant farther downslope. Both trees, though, are generally absent in a belt between 3,000 to 4,000 feet in elevation.

A familiar feature of the mountain South is the archipelago of Canadian “islands” along the spine of the Appalachian range. Peaks and ridges above 4,000-5,000 feet have climate and vegetation very similar to that of southern Canada and northern New England. American mountain ash (Sorbus americana) is a typical northern species also native to the highest reaches of Southern Appalachians.

It shares a habitat with red spruce and Fraser fir. The plant is also known as the “rowan tree,” a name apparently borrowed from the European mountain ash (Sorbus aucuparia), a species with similar characteristics. The Scandinavian word rowan means ‘red,’ referring to its bright berries. Roan Mountain, on the North Carolina-Tennessee border, supposedly received its name because of the numerous native rowan trees growing near its summit.

Mountain Phoenix

The deciduous tree has many showy characteristics, and consequently is often planted as an ornamental at lower elevations. Mountain ash leaves, ironically, have a somewhat tropical appearance, with spreading fronds that give the tree a full silhouette. In the spring, brilliant white blooms appear in large, flat clusters.

By late summer, the white flowers have matured into huge masses of red fruit that seem to have been randomly dropped into a bed of foliage. Although the leaves are shed in autumn, the fruit bunches often remain on the tree into early winter, providing a food source to several bird species.

Both mountain ash and holly berries contain less than 10% fat, not much compared to other berries such as dogwood, with 24% or more. As a result, migratory birds, needing energy on their long flight, feed heavily on high-fat berries, and generally ignore mountain ash and holly. Resident birds, however, depend on these low-fat berries late in the year when other food sources are no longer available.

Mountain ash, a member of the Rosaceae family, is closely related to the apple tree. Its fruit, although berrylike in appearance, structurally resembles a tiny apple and is botanically classified as a pome.

The common name of the tree is misleading, since it is not a true ash species. Perhaps the name originated from the fact that large concentrations of mountain ash literally rise from the ashes in locations that have been cleared by fire. Mountain ash seed remain dormant until the canopy layer of trees has been removed. Such disturbances are necessary for the survival of mountain ash, as it will not tolerate shade.

Glamorous Holly-wood

In contrast to the restricted, high-elevation range of American mountain ash, American holly (Ilex opaca) is widespread at elevations below 3,000 feet. It’s just one of many holly species found throughout the South and the southern mountains. The height of the American holly varies greatly, depending on the habitat. The tree is generally shorter in the mountains, resembling a large shrub.

Unlike mountain ash, holly is intolerant of fire. Rather than encouraging holly to flourish by removing competition, fire severely damages the tree and does not stimulate seed to sprout. Thriving in the understory forest layer, holly can easily compete with other trees.

Holly is dioecious, meaning that male and female flowers grow on separate plants. Berries are generated only on female trees.

Holly wood is characterized by a close grain with almost invisible growth rings. This type of grain gives the wood a smooth, vivid white appearance, making the timber ideal for ornamental woodwork such as inlays and scrollwork. Components in various musical instruments (piano keys, violin pegs) are often made from holly.

The most prevalent use of holly is, of course, for holiday decoration, a custom that goes back centuries in Europe where other holly species are found (the words holly, holiday, and holy have a common origin). The evergreen leaves and red berries make the plant attractive throughout the winter holidays.

Holly and mountain ash exhibit a curious blend of similarities and contrasts. The two shrubby trees are distinctive for their vibrant red fruit that remains on the trees into early winter. Resident birds depend upon their low-fat berries. Both species have close European relatives with identical common names.

Aside from these similarities, holly and mountain ash have contrasting attributes: the evergreen holly is found on the lower mountain slopes while the deciduous mountain ash is limited to the peaks; holly grows well in the shade and is suppressed by fire while mountain ash loves fire and open conditions.