Botanical Name: Alnus tenuifolia
Common Name: Mountain Alder, Thinleaf Alder  
Plant photo of: Alnus tenuifolia
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Water Saving Tip:

In general, lawns only need to be watered once every three days.

Check your irrigation controller and reduce watering times if necessary.

  • Anatomy

  • Culture

  • Design

Plant Type

Tree, Shrub


Height Range



Flower Color



Flower Season



Leaf Color

Green, Yellow


Bark Color

Brown, Grey


Fruit Color



Fruit Season



Full, Half, Shade





Growth Rate



Soil Type



Soil Condition

Rich, Well-drained, Moist


Soil pH

Acid, Neutral


Adverse Factors


Design Styles

Meadow, Water Garden, Wetlands, Woodland


Accenting Features

Fall Color, Multi-trunk Tree


Seasonal Interest

Winter, Fall


Location Uses

Background, Shrub Border, Park


Special Uses

Erosion Control, Screen, Mass Planting, Naturalizing


Attracts Wildlife

Birds, Butterflies

Information by: Stephanie Duer
  • Description

  • Notes

The Mountain Alder is a multistemmed large shrub or small tree, growing 15 to 20 feet tall and wide. The dull dark green leaves are thin and oval with serrated margins. Bark is grayish-brown, thin, and smooth, becoming reddish-gray and scaly with age. Catkins are produced during the growing season prior to blooming, and expand before the leaves emerge in the spring. Cone-like fruits enclose a very small winged seed that matures in late summer and persist through winter.
Grows best in course to medium, nutrient rich, moist soils and sunny to lightly shaded areas. Mountain alder can tolerate floods but not drought. It is able to survive extremely cold winters. The seeds, buds, and catkins are important winter food for various birds, including chickadees and goldfinches.