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Korean Mountain Ash Sorbus alnifolia

Other Common Name(s):

Phonetic Spelling
SOR-bus al-nih-FOH-lee-ah
Description

Sorbus alnifolia, or Mountain Ash, is a moderate to fast growing flowering tree that begins as pyramid-shaped but matures to a more rounded appearance. It grows best in moist, acidic, well-drained soils in full sun. A native of Asia, this tree prefers cool climates and will not grow well in the hot and humid summer conditions south of USDA Zone 7. It generally requires little pruning, but if you are driven to prune, apply your skills from late fall to early spring. It is less susceptible to pest and disease than other Sorbus spp., but is not a good street tree and is not tolerant of air pollution. The plant tolerates strong winds but not maritime exposure It is, however, easy to transplant.

Mountain Ash, is noted for its attractive form, creamy white flowers, simple beach-like leaves, red fall fruit and good fall color. Golden orange fall color can be outstanding.

Insects, Diseases, and Other Plant Problems:

Mountain Ash is noted for its resistance to borers that attack other species of mountain ash. It is considered to be one of the best of the mountain ashes because of its pest resistance and form. However, bacterial fireblight can be a severe problem, 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 aphids, sawfly and scale. Stressed trees are generally more susceptible to attack from canker and borers.

See this plant in the following landscape:
Cultivars / Varieties:
  • Redbird
  • Skyline
Redbird, Skyline
Tags:
#deciduous#shade tree#tree#winter interest#flowering tree#wind tolerant#wet soils tolerant
 
Cultivars / Varieties:
  • Redbird
  • Skyline
Redbird, Skyline
Tags:
#deciduous#shade tree#tree#winter interest#flowering tree#wind tolerant#wet soils tolerant
  • Attributes:
    Genus:
    Sorbus
    Species:
    alnifolia
    Family:
    Rosaceae
    Life Cycle:
    Woody
    Recommended Propagation Strategy:
    Seed
    Country Or Region Of Origin:
    Temperate Asia
    Wildlife Value:
    Attracts birds.
    Dimensions:
    Height: 30 ft. 0 in. - 50 ft. 0 in.
    Width: 20 ft. 0 in. - 30 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Tree
    Woody Plant Leaf Characteristics:
    Deciduous
    Habit/Form:
    Pyramidal
    Rounded
    Growth Rate:
    Rapid
    Maintenance:
    Medium
    Texture:
    Medium
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Soil Texture:
    Clay
    Loam (Silt)
    Sand
    Soil pH:
    Acid (<6.0)
    Soil Drainage:
    Good Drainage
    Moist
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    3a, 3b, 4b, 4a, 5b, 5a, 6b, 6a, 7a, 7b, 8b, 8a
  • Fruit:
    Fruit Color:
    Orange
    Red/Burgundy
    Fruit Value To Gardener:
    Showy
    Display/Harvest Time:
    Fall
    Fruit Type:
    Berry
    Pome
    Fruit Length:
    < 1 inch
    Fruit Description:
    Flowers are followed by pink to orange to scarlet berry-like pomes (to 5/8 inch long) that ripen in fall and remain on the tree even after leaf-drop.
  • Flowers:
    Flower Color:
    White
    Flower Inflorescence:
    Corymb
    Flower Value To Gardener:
    Showy
    Flower Bloom Time:
    Summer
    Flower Petals:
    4-5 petals/rays
    Flower Size:
    1-3 inches
    Flower Description:
    Dense flattened corymbs (to 3 inches across) of 6 to 10 small 5-petaled white flowers appear in May.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Deciduous
    Leaf Color:
    Green
    Leaf Feel:
    Glossy
    Leaf Value To Gardener:
    Showy
    Deciduous Leaf Fall Color:
    Brown/Copper
    Orange
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Lanceolate
    Ovate
    Leaf Margin:
    Dentate
    Hairs Present:
    Yes
    Leaf Length:
    3-6 inches
    Leaf Description:
    Dark green 2 to 4 inch leaves that turn orange, golden brown in the fall. Leaves are simple (leaves of most other species of mountain ash are compound).
  • Bark:
    Bark Color:
    Light Gray
    Surface/Attachment:
    Smooth
    Bark Description:
    The smooth, gray, beech-like bark is quite noticeable in winter.
  • Stem:
    Stem Is Aromatic:
    No
  • Landscape:
    Landscape Theme:
    Winter Garden
    Design Feature:
    Flowering Tree
    Attracts:
    Songbirds
    Resistance To Challenges:
    Wet Soil
    Wind