Walnut wood is celebrated for its rich color, attractive grain, and natural durability. It is sourced from the genus Juglans, which encompasses various species globally. The term “walnut” is frequently applied to several woods with a dark appearance, though only those from the Juglans genus are considered true walnuts. Understanding the specific botanical source determines the true origin and properties of the wood.
The Primary Commercial Walnut Species
American Black Walnut (Juglans nigra) is a premier domestic hardwood native to the central and eastern regions of North America. The tree is valued for its heartwood, which features a deep, dark chocolate-brown color, sometimes exhibiting streaks of purple or reddish hues. It is a dense and stable wood with a semi-ring-porous grain structure, making it an ideal choice for fine furniture, cabinetry, and specialty items like gunstocks.
English, or Persian, Walnut (Juglans regia) is the other globally prominent source, with a native range stretching from Southeastern Europe through the Middle East to Central Asia. This species generally yields a slightly lighter heartwood, typically a grayish-brown or soft mouse-brown, which can darken over time. This species is the source for much of the commercial walnut sold outside of North America. The wood is renowned for its stability and is widely used in high-quality veneer, architectural millwork, and decorative paneling.
Regional and Less Common Walnut Varieties
Butternut, or White Walnut (Juglans cinerea), grows throughout the eastern United States and Canada, sharing a similar range with American Black Walnut. This wood is noticeably softer and lighter in color than its cousin, often featuring a pale tan or beige heartwood. Unfortunately, the species is now critically endangered in much of its range due to the pervasive Butternut Canker disease, making its lumber a rare find.
Claro Walnut (Juglans hindsii) is native to California and Oregon, often called California Black Walnut. The wood is known for its highly figured grain, which can include dramatic curls and burls. Its heartwood displays a mix of colors, ranging from light brown to deep chocolate with streaks of gray, purple, or red. A highly sought-after “marbled” figure is created when this species is used as a rootstock for grafting with English Walnut trees, producing a distinctive color blend at the graft line.
Woods Frequently Misidentified as Walnut
Many woods are commercially labeled as “walnut” due to their similar dark appearance, despite being botanically unrelated to the Juglans genus and imported from different geographic regions. African Walnut is a common trade name used for species such as Lovoa trichilioides and Mansonia altissima, which grow in West and Central Africa. These woods are used as a lower-cost substitute because their heartwood darkens to a golden or reddish-brown with dark streaks.
A key difference lies in the wood’s microscopic structure; true walnut is semi-ring-porous, while these African species are diffuse-porous, meaning their pores are more uniformly distributed. Another common misnomer is New Guinea Walnut, or Pacific Walnut, sourced from the Dracontomelon dao tree in Southeast Asia and the Pacific Islands. This wood is generally much softer and lighter than true walnut, but it is marketed under the name because its heartwood features dark, irregular streaks against a gray-brown background.