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Common Alder Alnus glutinosa

Other Common Name(s):

Previously known as:

  • Alnus vulgaris
  • Betula alnus var. glutinosa
  • Betula glutinosa
Phonetic Spelling
AL-nus glu-ti-NO-sa
Description

The Black Alder is a member of the birch family and is also commonly known as the Common Alder, European Alder, and Aune Glutineux.  It is a medium-sized deciduous tree native to Europe, western Asia, and northern Africa.  Early colonists from Europe brought the Black Alder to North America.  The genus, Alnus, is Latin for alder.  The species name, glutinosa,  is reflective of the sticky texture of its young leaves and stems. The tree is readily identifiable by its glossy and toothed margined leaves as well as by its dangling catkins seen in the spring and cone-like fruits seen in the fall.  The Black Alder was planted in the United States primarily as an ornamental tree and to control erosion.  The tree is often found growing in wetlands, as well as near ponds, lakes, and rivers.  It is used to improve the soil on recently cleared land.  The tree roots can add nitrogen to the soil by forming a relationship with a nitrogen-fixing bacteria known as Frankia alni.  The Black Alder may sucker and form dense thickets.  It can spread aggressively.  This tree is best used in sites that have poor soil or low-lying wet areas.

The Black Alder may be confused with Alnus incana, which is more shrub-like and grows only to a height of 32 feet.

See this plant in the following landscape:
Cultivars / Varieties:
  • Aurea
    emerges with yellow leaves
  • Imperalis
    strongly dissected leaves
  • Lacinita
    shallowly dissected leaves
  • Pyramidalis
    narrower tree spread, resists disease
Aurea, Imperalis, Lacinita, Pyramidalis
Tags:
#sun#deciduous#full sun#partial shade#tree#winter interest#wet sites#flooding#fast growing#multistemmed#pest resistant#transplant#dry soils tolerant
 
Cultivars / Varieties:
  • Aurea
    emerges with yellow leaves
  • Imperalis
    strongly dissected leaves
  • Lacinita
    shallowly dissected leaves
  • Pyramidalis
    narrower tree spread, resists disease
Aurea, Imperalis, Lacinita, Pyramidalis
Tags:
#sun#deciduous#full sun#partial shade#tree#winter interest#wet sites#flooding#fast growing#multistemmed#pest resistant#transplant#dry soils tolerant
  • Attributes:
    Genus:
    Alnus
    Species:
    glutinosa
    Family:
    Betulaceae
    Uses (Ethnobotany):
    For many centuries in Europe, the Black Alder provided hardwood for timber. The wood was also used for carving, such as wooden shoes.
    Life Cycle:
    Woody
    Recommended Propagation Strategy:
    Seed
    Country Or Region Of Origin:
    Europe, northern Africa, western Asia
    Distribution:
    Argentina; Azores; Chile; USA--CT, IL, IN, IA, KS, KY, MA, MI, MN, MO, MS, NJ, NY, OH, PA, RI, TN, VA, VT; WI; Ontario; New Zealand
    Wildlife Value:
    The tree provides food for deer, rabbits, and birds as well as offers shelter for nesting birds.
    Particularly Resistant To (Insects/Diseases/Other Problems):
    Tough adaptable plant; few pest problems; tolerates short term flooding; easy to transplant; wet, infertile, or dry soil
    Dimensions:
    Height: 40 ft. 0 in. - 60 ft. 0 in.
    Width: 20 ft. 0 in. - 40 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Tree
    Woody Plant Leaf Characteristics:
    Deciduous
    Habit/Form:
    Multi-stemmed
    Pyramidal
    Growth Rate:
    Rapid
    Maintenance:
    Low
    Texture:
    Medium
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    Clay
    Loam (Silt)
    Sand
    Soil pH:
    Acid (<6.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Good Drainage
    Moist
    Occasionally Wet
    USDA Plant Hardiness Zone:
    3a, 3b, 4b, 4a, 5a, 5b, 6a, 6b, 7b, 7a
  • Fruit:
    Fruit Color:
    Black
    Brown/Copper
    Green
    Fruit Value To Gardener:
    Long-lasting
    Display/Harvest Time:
    Fall
    Fruit Type:
    Samara
    Fruit Length:
    < 1 inch
    Fruit Width:
    < 1 inch
    Fruit Description:
    The female catkins develop into wood cones about 3/4 inches long. Inside the cones are winged seeds that are released in the fall when they have matured. The cones remain on the tree through the winter months and into the next growing season.
  • Flowers:
    Flower Color:
    Brown/Copper
    Red/Burgundy
    Flower Inflorescence:
    Catkin
    Flower Value To Gardener:
    Showy
    Flower Bloom Time:
    Spring
    Flower Size:
    1-3 inches
    Flower Description:
    The Black Alder produces male and female florets on the same tree. The male florets have clusters of 2-5 catkins that measure 2 to 3 inches long. They are reddish-brown, long, and drooping. The female florets are reddish-brown and have clusters of 2-5 cone-like catkins. Initially, they are only 1/4 inch long, but as they mature they measure 3/4 to 1 inch long and 1/2 inch wide. The blooming period occurs in early spring before the leaves emerge. The florets are cross-pollinated by the wind. After blooming the male catkins wither and fall away, but the female catkins remain on the tree through summer. In the fall, the female catkins release their seeds.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Deciduous
    Leaf Color:
    Green
    Leaf Feel:
    Glossy
    Deciduous Leaf Fall Color:
    Brown/Copper
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Obovate
    Orbicular
    Leaf Margin:
    Crenate
    Dentate
    Undulate
    Hairs Present:
    Yes
    Leaf Length:
    3-6 inches
    Leaf Width:
    3-6 inches
    Leaf Description:
    The maximum leaf size is 5 inches long and 3 to 4 inches wide. Their shape is obovate or orbicular-obovate. The margins are crenate, dentate, and slightly undulated. The upper leaf surface is dark green and mostly smooth. The underside is a pale green and glabrous to slightly hairy along the leaf veins. The young leaf surface is heavily coated with resin. In the fall, the leaves will either remain green or turn brown. During the winter, the leaves may either drop off or wither on the tree. Parasites may occur such as Dasineura tortilis or Aceria nalepai.
  • Bark:
    Bark Color:
    Dark Brown
    Green
    Light Brown
    Light Gray
    Surface/Attachment:
    Furrowed
    Bark Plate Shape:
    Irregular
    Bark Description:
    The bark on a mature tree is gray to brownish-gray. It is divided into flattened plates that are separated by shallow furrows. Young trees have light gray to greenish-gray bark.
  • Stem:
    Stem Color:
    Brown/Copper
    Gray/Silver
    Stem Is Aromatic:
    No
    Stem Lenticels:
    Not Conspicuous
    Stem Surface:
    Smooth (glabrous)
    Stem Description:
    The stems are smooth and covered with glutinous glands. The stem color in winter is brown or gray.
  • Landscape:
    Landscape Location:
    Coastal
    Pond
    Riparian
    Landscape Theme:
    Rain Garden
    Winter Garden
    Design Feature:
    Barrier
    Attracts:
    Small Mammals
    Songbirds
    Resistance To Challenges:
    Dry Soil
    Insect Pests
    Wet Soil
    Problems:
    Weedy