Walnut, English

English Walnuts are tall broad-headed trees with large leaves. Most of the species are hardy, and very valuable part trees, with a massive, straight trunk, and a light and airy broad top. Though many fungi and insects prey on the walnut, none of them do very serious damage.

Typically they are a medium to large tree (to 100 ft) with a spreading crown. The name “walnut” derives from the corruption of “Gaul nut”, coined by the French.

The LEAVES are odd-pinnately compound with prominent, herring-bone venation in the ovate, acute-tipped leaflets; entire margins.

The FLOWERS – All Juglans spp are monoecious, bearing male and female reproductive organs on separate flowers on the same tree. Although J. regia is self-fertile, it is heterodichogamous, either protandrous or protogynous depending on cultivar. Catkins ( inflorescences) are borne laterally on 1-yr wood, and pistillate flowers are borne terminally (or laterally in newer cvs) on current season’s wood in spikes of typically 2-4 flowers. Each catkin may produce 2 million pollen grains. Pistillate flowers lack visible sepals and petals, and are small and green.

The FRUIT is a nut. The green, fleshy, shuck (involucre + outer ovary wall) covers the nut until maturity, when it dehisces irregularly, releasing the nut. There are fewer nuts per cluster, but more nut clusters compared to pecan.

Walnuts and most tree nuts are relatively slow to bear, often a 2-5 yr juvenile period must pass, and the first significant yields @ 8 yr. “Payne” types bear earlier. Walnuts mature from 4.5-5 months after flowering, and are harvested in the fall.

The FRUIT HUSK yields a valuable oil and a yellow dye when pressed; the oil is used in soaps, paints and dyes. The WOOD is used for furniture and gunstocks; heavy, fine-grained.

SEED SHELLS are ground and used as anti-skid agents for tires, blasting grit, activated carbon, and sometimes as an “adulterant” of spices.