The Walnut tree, genus junglans belongs to the order of shrubs and trees known as Juglandeae, representing five genera and twenty one species, spread across the northern temperate climate of the Old World to the southeast Europe and east to Japan. Its original home is believed to be the north of Iran (Persia).

One of the tallest and largest of trees in the Junglandeae order the walnut tree grows rapidly and usually reaches a height of ten meters in ten years. However, it is not infrequently that they grow to a height of about twenty to forty meters, with a trunk diameter of two meters or more and limbs spreading ten to twelve meters from the stem.

The leaves and flowers of the walnut tree commonly appear in spring; but there are in cultivation early and also late varieties. The leaves are composed from five up to nine leaflets, oval shaped and somewhat terminal point. They are smooth and with an unusual shade of green.

The male cylindrical catkins of the Walnut tree are produced from leafless shoots from the previous year. they are about 10 cm in length and bear a large number of tiny flowers. Female flowers appear at the peak of the current year's leafy shoots. The fruit or nuts of the walnut tree have thick green outer husks that burst, when ripe, and within it there is a woody nut called walnut.

The collected commonly by thrashing the branches with long poles. While this damages off many of the smaller branches it will also cause new spurs to grow that are generally female with fruit-bearing flowers. The nuts when ripe are eaten as a snack during the autumn and winter months.

When young the fruits are mostly used pickled either unripe or whole, or just the kernels, as sweetmeats. There are two commercially important walnut tree species, J. regia for nuts and timber and J. nigra just for timber. These two species have the same cultivation requirements and they are grown widely in temperate zones.

Walnut, j. regia, j. nigra

The key to successful fruit and nut production is the presence of a beneficial environment for the trees that bear them.