Red Alder Alnus rubra

Red AlderAlnus rubra

CharacteristicsMedium-sized fast-growing broad-leaf tree, grows up to 40 feet. Name derives from bright rusty red color that develops in bruised or scraped bark. Bark mottled, ashy-gray and smooth, and usually covered with lichens as the tree ages. Leaves oval, 2-5 inches long, with bluntly serrated edges, slightly rolled under; distinct point at the end.

Flowers/FruitFlowers occur as either male or female clusters. Male flowers in long, drooping, reddish catkins, and female flowers in short, woody, brown cones that are shed in fall and winter.

Habitat ValueMule Deer browse the twigs in fall and twigs and buds in the winter and spring; Beaver eat the bark. American Goldfinches and Pine Siskins feed on alder seeds.

Home Garden ApplicationsGrows easily; used as “reclamation” tree. Should be planted well away from drainpipes, sewage pipes, and water lines, as the roots may invade and clog the lines. Tent caterpillars and leaf beetles commonly found in upper branches.