Red Alder

Red alder (Alnus rubra)
Alnus rubra

Red alder is a fast-growing deciduous tree well suited for disturbed and infertile soils, and an excellent nitrogen fixing plant. Generally grows to a height of 40-50 feet, sometimes reaching up to 80 feet. Red Alder flowers in March with hanging, cylindrical reddish-orange catkins. Leaves turn a slight golden color in the autumn.

In the open, red alders grow into a broadly conical shape with spreading branches. It is an excellent wildlife tree that provides cavity-nesting opportunities and forage for a wide range of songbirds. It also serves as a host plant for swallowtail butterfly larvae.

Best in sun to part shade with moist soils.


  • Light Requirements: Full Sun, Part Shade
  • Water Requirements: Moist
  • Ease of Growing: Easy to grow
  • Growth Rate: Moderate
  • Spreads: No
  • Wildlife Support: Pollinators, Pest-eating Insects, Birds or Mammals
  • Edible: No
  • Mature Height: 40-50ft
  • Mature Width: 40-50ft