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Sorbus americana

Common Name(s):
American mountainash
Categories:
Native Plants, Shrubs, Trees
Comment:

Sorbus americana, called American mountain ash, is a small, deciduous, understory tree (sometimes a shrub) that is native to northeastern North America from Newfoundland to Manitoba south to northern Illinois, northern Michigan and New Jersey plus further south in the Appalachians to Georgia. It typically grows to 15-30’ tall with an open rounded crown. It is noted for its attractive form, white spring flowers, serrate compound-pinnate leaves and bright orange-red fall fruit. Smooth, gray bark becomes scaly with age.  This is a short lived plant, having a short trunk with spreading branches.

Its bark is smooth with numerous lenticels when young.  As the tree ages, cracks, splits, and scaly patches develop.

Regions:  Mountain

Seasons of Interest: 

  Blooms:  Summer            Nut/Fruit/Seed:  Fall into winter

Wildlife Value:   This plant has no resistance do damage from deer.  Its fruits are eaten by many birds and mammals. 

Insects, Diseases, or Other Plant Problems: Bacterial fireblight can be a severe problem of the American mountain ash, causing scorched leaves at the branch ends. Scab can cause significant defoliation. Cankers, crown gall, powdery mildew and rust may also occur. Insect visitors include borers, aphids, sawfly and scale. Stressed trees are generally more susceptible to attack from canker and borers.

Height:
10-30 ft.
Flower:
Dense flattened clusters (corymbs to 3-6” across) of very small 5-petaled white flowers (each to 1/4” wide) appear in May on the American mountain ash. Flowers are followed by bright orange-red berries (each to 5/16” diameter) that ripen in late summer and remain on the tree after leaf-drop. Berries are attractive to birds and animals, but too acidic to be eaten fresh off the tree by humans. Berries may be made into jellies.
Zones:
2-6
Habit:
Deciduous
Site:
The American mountain ash is best grown in moist, acidic, humusy, well-drained soils in full sun. As the common name suggests, this is a tree of cool mountain climates that dislikes dry soils and hot and humid summers. It will not grow well in the deep South below USDA Zone 6. It is somewhat intolerant of urban pollution. It generally requires little pruning. Prune if needed from late fall to early spring.
Texture:
Smooth
Form:
Short trunk with spreading branches; narrow open rounded crown with age
Exposure:
Sun; range of soil types
Fruit:
Bright red to orange-red berries in fall that last into the winter
Width:
10-30 ft.
Growth Rate:
Slow
Leaf:
Each odd pinnate, alternate leaf of the American mountain ash (6-10” long) typically has 9-17 sharply serrated, lance shaped, dark green leaflets (2-4” long) with gray-green undersides. The foliage turns yellow in fall. Mountain ashes usually have ash-like leaves, but are members of the rose family, and are not related to true ashes (Fraxinus), which are in the olive family.
Tags:
birds, deciduous, flowering, showy

NCCES plant id: 558

Sorbus americana Sorbus americana
Chris M. Morris, CC BY - 4.0
Sorbus americana Sorbus americana
jpc raleigh, CC BY-NC - 4.0
Sorbus americana Sorbus americana
WhatsThisThen, CC BY-NC-ND - 4.0
Sorbus americana Sorbus americana
Kent MeFarland, CC BY-NC - 4.0
Sorbus americana Sorbus americana
Jean Pierre Bluteau, CC BY-NC - 4.0
Sorbus americana Sorbus americana
Superior National Forest, CC BY - 4.0
Sorbus americana Sorbus americana
Superior National Forest, CC BY - 4.0
Sorbus americana Sorbus americana
Kent McFarland, CC BY-NC - 4.0