Butternut

About Butternut in Alberta

Butternut is a foreign Alberta tree, but it has real planted relevance in the province, especially through Edmonton guidance and standards and older Calgary trial history. In Alberta it should be understood as a rare planted walnut with educational, documentary, and horticultural value rather than as a native or naturalized tree. It is best recognized by its large pinnately compound leaves, pale bark, hairy buds and twigs, and elongated sticky-husked nuts. For ARA purposes, the most important added layer is that Butternut is federally Endangered in Canada because of butternut canker, which makes healthy Alberta plantings especially interesting as western documentary specimens.

Identification: Leaves are alternate, pinnately compound, and large, usually with 11-17 leaflets and sometimes more. The rachis and young leaf parts are hairy, and the terminal leaflet is usually well developed, which helps separate Butternut from Black Walnut.

Alberta range and habitat: Butternut should not be treated as part of Alberta's native wild-tree flora. No strong evidence supports wild or naturalized Alberta occurrence.