Black walnut leaves are alternate and pinnately compound
and large in size, reaching 12 to 24 inches in length. Each
leaf (shown here) is made up of 15 to 23 leaflets. The
terminal leaflet is often absent.
The margin of the black walnut leaf is singly
toothed.
Black walnut and English walnut differ in the number of
leaflets, the shape of the leaflets, and the leaflet margin.
black walnut leaves have a greater number of leaflets
(15-23) than English walnuts (5-9). English walnut leaflets
have more oval shaped leaves while black walnut leaves are
generally smaller and narrower in shape. Black Walnut
leaflets have toothed margins while English walnut leaflet
margins are entire.
Black walnut leaves generally have more leaflets (15-23)
compared to butternut (11-19). The leaflet size is of black
walnut is typically smaller than butternut. Also butternut
leaves are hairy on their midvein, while black walnut is
hairless.