All About Mountain Ash Trees

The mountain ash tree is from the genus Sorbus and is also commonly referred to as the rowan tree. The mountain ash is from the Rose family and native to Europe, but in the 1800's Americans began cultivating it. The American mountain ash (Sorbus americana) and Northern mountain ash (Sorbus decora), provide many animals with food; its white flowers and red berries add beauty to any yard. 

Description of the Mountain Ash

The American mountain ash grows to an average height of 10 to 30 feet tall. Its pale brown bark is smooth; the trunk of the mountain ash is slender and short. The round, narrow crown of leaves reaches out to a width of 3 to 10 feet. Its leaves are alternately compound with small leaflets. The leaves reach to the length of 13 to 17 inches and turn yellow and purple in the autumn. Creamy-white flowers bloom throughout summer until they are replaced by red berries in August.

The American mountain ash and Northern mountain ash are very similar except for the fact that the Northern mountain ash's berries are about twice as big (1/2 inch in diameter) and orange-red instead of bright red like the American mountain ash, and the leaflets of the American mountain ash are about 3 times as long as wide, while the Northern mountain ash's leaflets are more rounded. Also, the American mountain ash's leaflet are hairy underneath, and the Northern mountains ash's leaflets are not.

Cultivation of the Mountain Ash

Mountain ash trees are hardy in USDA zone 3 to 8. They grow best in moist, fertile and acidic soil with a pH range of 4.7 to 6.0. Other soil requirements include an organic matter percentage of at least 1.7%. The Mountain ash does not grow well in shade or dry soil.

Propagation of the Mountain Ash

The Mountain ash is propagated sexually by seed. Its seeds needs at least 6o days of cold stratification between the temperature of 33 to 41 degrees Fahrenheit before it will germinate. Sow seeds in the autumn or winter. For best results, plant in July since the seeds will germinate better the next spring if they are introduced to warm temperature before the winter. The seedlings are hardy and resistant to many insects and diseases and so they are not required to be kept indoors. If a mountain ash tree is cut or burned down, it will sprout from its stump.

Uses of the Mountain Ash

The mountain ash is often planted for windbreaks and its red berries are edible for human consumption. The berries are too acidic to be eaten raw and are commonly used to make jellies or wine. The mountain ash provides food for many birds, deer, moose, rabbits, squirrels and gypsy moth larvae. In the past, the inner bark and fruit of the mountain ash has been used for medicinal purposes.


Finally, the mountain ash is used for ornamental purposes, adding the colors of green, white, red, yellow and purple to your yard!