Juglans nigra, Black Walnut

Common Name: Black Walnut

Juglans nigra (Black Walnut) is a large, broadleaf tree which can reach 30–40m high. The tree gets its name from its dark, heavily ridged bark which occurs even when it is still young. The leaves are pinnate and larger than that of the common walnut (Juglans regia) with more leaflets. Individual leaflets are oval, pointed, irregularly toothed and hairy underneath. Crushed leaves have a strong smell.

Both male and female flowers appear from late May–early June. The male flowers are on 8–10cm-long catkins that droop from the branches. Female flowers appear in clusters. In autumn, flowers turn to a brownish-green plum-like fruit. The brown nut is held inside this large semi-fleshy husk which is rougher than that of common walnut. The shells are notoriously hard to break; drying them out makes it easier to crush and open the shells.

Identified in winter by: the segmented pith, or spongy tissue, inside the twig. At their base, buds have horseshoe-shaped leaf scars, or marks, left by fallen leaves. Not to be confused with Common Walnut; Black Walnut has a greater number of leaflets (7–9 pairs) with toothed edges. Black Walnut leaflets are also generally smaller and narrower than those of common walnut.

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