Filbert is the name for both the nut and the plant of a group of trees and shrubs that are closely related to the birches. The nuts are also called hazelnuts and cobnuts (see HAZEL). Some filberts grow 60 feet (18 meters) tall. Other filberts are shrubs that normally grow from 2 to 30 feet (0.6 to 9 meters) high. Filberts are native to North America, Europe, and Asia. They thrive in orchards in the Pacific Northwest in the United States and in southern Europe. Larger nuts grow on the cultivated trees than on the wild ones. The seeds taste better roasted than raw.

The nuts form in compact clusters, with each nut encased within its own husk. The nuts have smooth and hard but thin and brittle shells. The kernels are single.

Scientific Classification. Filberts belong to the birch family, Betulaceae. The scientific name for most cultivated varieties is Corylus avellana.

Contributor: Richard A. Jaynes, Ph.D., Horticulturalist and Consultant, Broken Arrow Nursery.