How to identify Hazel alder (Alnus serrulata)

How to identify Hazel alder (Alnus serrulata)

Hazel alder, also known as Brook-Side Alder, Smooth alder

Hazel alder is a modest-sized deciduous tree reaching heights of about 10 to 15 feet (3 to 4.5 meters) tall. The foliage exhibits alternate arrangement with distinctive wavy, toothed edges and a roughly textured underside. Its bark is a smooth gray-brown, marked by a fluted texture. In late winter, hazel alder reveals dimorphic flowers: slender green catkins for males, and red blooms for females. By fall, the tree produces seeds that remain attached through the winter season.

Lifespan: Perennial

Plant Type: Tree, Shrub

Leaf Type: Deciduous

Quickly Identify Hazel alder

Deciduous tree, 10-15 feet (3-4.5 meters) tall

Distinct male and female flowers: yellow-brown and red catkins

1-inch (2.54 cm) fruiting cones with winged nutlets

Dull green leaves with saw-like teeth, 2-4 inches (5-10 cm)

Smooth gray bark with inconspicuous lenticels, sleek appearance

Detailed Traits of Hazel alder

Leaf Features

Hazel alder leaves are dull green and range from 2 to 4 inches (5 to 10 cm) long. They feature serrulate margins with small, saw-like teeth along the edges. Each leaf has a pointed tip and a wedge-shaped base. The vein pattern is prominent, aiding in identification. The texture is slightly rough to the touch, supporting its resilience in various environments.

Learn About the Leaf Glossary

Flower Features

Hazel alder displays distinct male and female flowers on the same plant. The male flowers form yellow-brown catkins, slender and elongated, typically 1 to 2 inches (2.5 to 5 cm) long. Female flowers are shorter, around 0.5 inches (1.3 cm), and appear as red catkins. Blooming in late spring, these flowers lack a noticeable scent but showcase vivid coloration critical for identifying hazel alder.

Learn About the Flower Glossary

Fruit Features

The fruit of hazel alder appears as distinctive 1-inch (2.54 cm) long fruiting cones, or 'strobiles', measuring up to 3/4 inch (1.9 cm) long. These strobiles house winged nutlets encased within woody scales. Upon maturing, the fruit turns a dark brown color in the fall and remains attached to the plant into winter. The finely textured cones have a likeness to miniature pine cones, and are a source of food for various butterflies, mammals, and birds that feed on the tiny seeds within.

Learn About the Fruit Glossary

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