WSU Clark County Extension

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Red Alder

Scientific name: Alnus rubra

Type:Deciduous tree
Plant Requirements
Zone:5 to 8
Sun:Full sun
Plant Characteristics
Height:60 ft
Width:30 ft
Bloom:Spring flowers
Bloom Time:April
Bloom Color:Yellow
Additional Characteristics



Wildlife value

Description Red Alder is the most common native hardwood in the Pacific Northwest extending from southern California north to southeastern Alaska. This species is also known as Oregon alder, western alder, and Pacific coast alder

A medium sized tree reaching 50’-60’ in height and 30’ in width. Typically has a moderately straight bole (trunk) with an open, broadly pyramidal or dome-shaped crown. The lower trunk is usually free of branches as this species does not with-stand shade, thus limiting branch formation.

Leaves are alternately arranged, simple, deciduous, ovate in shape and are 3”-6” in length. The leaf veins are prominently penniveined with doubly serrated margins. The margins of the leaves are coarsely toothed and roll under.

Female catkins are short and thick, and are borne at the ends of branchlets. Male catkins and are slender and hang in a pendent manner.

The bark of Red Alder is smooth, light gray, but turns white with age. It is very common to find the trunk covered with lichens.

Red alder is found on a wide range of soils, from well-drained gravels or sands to poorly drained clays or organic soils.

Tent caterpillars and leaf beetles are commonly found on Red Alder but do no serious damage.
For assistance, contact Dr. Charles Brun (, (360) 397-6060 5701
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