The American mountain ash (Sorbus americana), also known as mountain ash or roundwood, is a deciduous small to medium size tree, attaining a height of 30 feet (maximum 71 feet), and a trunk diameter of more than 1 foot. It does not grow rapidly and is considered a short-lived species.
The leaves are alternate, pinnately compound, 6 to 10 inches long with lance-shaped leaflets that are 2 to 3 inches long; fine and sharp toothed margins, dark yellow-green on top and paler beneath.
The fruits are pomes (berry-like), 1/4 inch in diameter, in large clusters, and an orange-red color when mature.
Hardiness: Zones 3 through 9
Growth Rate: Moderate to Fast
Mature Shape: Slightly pyramidal, upright with a rounded crown
Height: 50 to 80 feet
Width: 50 to 70 feet
Site Requirements: Native to Iowa, ash trees grow best in full sun and moist, well-drained soils. Ash trees are tolerant of a wide range of soil conditions.
Flowering Dates: May - July
Seed Dispersal Dates: August - March
Seed Bearing Age: 15 Years
Seed Bearing Frequency: Yearly
Seed Stratification: Seeds need cold stratification for 2 months at 34°F to 40°F
The twigs are thick, smooth, and gray to red color. The bark is light gray-brown, smooth on younger trunks, and rougher on older ones.
Considered a beautiful ornamental tree with no commercial value, it is commonly found in disturbed forest edges, cold swamp and bog margins, and rocky outcrops. Distinctly a northern species, it ranges from Newfoundland to Manitoba south to the northern portions of the United States and along the Appalachian Mountains to North Carolina.
Diseases that Can Affect American Mountain Ash
Insects that Can Affect American Mountain Ash
- Emerald Ash Borer
- Ash Spider Mite
- Pear Sawfly or Pearslug
- Ash Plant Bug
- Ash Sawflies
- Ash/Lilac Borer
- Leafcutter Bees
- Oystershell Scale