Thinleaf Alder

Alnus tenuifolia

Family: Betulaceae or Birch

Leaves: Alternate; simple; ovate-oblong; 2" to 4" long; deciduous; sometimes slightly lobed; doubly serrate; thin; glabrous; dark green above, pale yellow-green beneath; petiole short.

Twigs/buds: Twigs slender; with orange lenticels or bumps; buds stalked, bright red, 1/4" to 1/3" long.

Flowers/fruit: Fruit a small nutlet borne in small, 1/3" to 1/2" long, oval "cones" (catkins or strobili).

Bark: Thin; smooth; brownish-red.

Wood: Unimportant. Alder wood in general is light and soft with conspicuous rays, white to pinkish color, and indistinct heartwood; used in furniture, veneer, and carvings; diffuse porous.

General: Shrubby tree native to much of the western U.S. and Canada, including moist canyon sites in Utah. Nitrogen fixer. Likes moist, cool sites along streams. Somewhat shade tolerant when young, but becomes intolerant when older. Welsh et al. consider this species to be Alnus incana or speckled alder.

Landscape Use: Seldom planted and no cultivars are available, but could be planted on appropriate, moist sites where native plants are desired. Zones 1-7. I have seen some very large, narrow crowned alders growing in Logan that were probably European or common alder (Alnus glutinosa). These were a little unkempt, but otherwise nice and several cultivars are available. Zones 3-7.

Comments and Limitations:

• Prefers abundant water, but may survive on drier sites.