Juglans
These deciduous trees are found wild from southeast Europe to the Himalayas, through China to Manchuria and Japan, and in North and South America. Most of them are hardy. Various species of Juglans are commonly known as Walnut trees. These trees are grown for their beauty, some for their timber and some for their edible nuts. The leaves, sap and husks will definitely stain anything with which it comes in contact. Walnuts are monoecious, that is, male and female flowers are produced on the same tree. The male flowers are produced in long catkins and the inconspicuous, greenish female flowers are borne in clusters. Male and female flowers are not open at the same time, so in order to pollinate, two or three trees should be planted near each other. J. regia, the English or Persian Walnut grows from 80 to 100 feet high and produces nuts popularly called English Walnuts. There are many varieties that vary in hardiness, nut size, and thickness of the nutshell. The English Walnut may be grown over a large portion of the U.S., but nut production is confined mainly to California and parts of Washington and Oregon. J. nigra, the Black Walnut, is hardier than the English Walnut and is grown for ornament, its timber, and its nuts. The leaves are from 1 to 2 feet long, alternate, pinnately compound, with 13 to 23 ovate-lance-shaped leaflets which are attached to a stout, downy rachis. The leaflets are from 2 to 4 inches long and yellowish-green with a paler and often fuzzy underside. The walnuts are round and 1� to 2 inches in diameter with a sculptured bony shell. They are surrounded by a slightly fleshy, greenish husk during the summer, at that time, the nut is 2 to 3 inches in diameter. They ripen in October and drop from the trees. The Black Walnut grows from 50 to 75 feet high. The Black Walnut is also valued for its wood, which is a rich, dark brown color. It is heavy, strong, hard and very durable when in contact with the soil. It is used in making furniture and gunstocks. The nuts are rather oily with a strong, unique flavor. They are widely used in cooking. The hulls that surround the nuts were used as a dye by the early pioneers.
Pot Cultivation
Walnut trees will flourish in well-drained, loamy soil, although the American Black Walnut does well on light land. They should be planted in the fall or early spring. The young plants need to be pruned to encourage the formation of a single, central shoot. All pruning should be done between June and December because if they are pruned in late winter or spring, they "bleed" profusely. The English Walnut should be grown on deep, fertile, light (sandy) ground, which is free from alkali. It needs to be moist all the time.
Propagation
Seeds should be used to propagate the wild species whenever possible. They should be placed in moist sand for the winter months to prevent their drying out, and be sown in well-drained, light, loamy soil in the spring. They should be given protection from vermin by covering them with a wire netting or some other covering. It would be beneficial if the seeds could be sown where they are to grow permanently, because transplanting could seriously stunt their growth. If they are started in a nursery bed, the seedlings should be lifted at the end of the season and the roots carefully trimmed; they should then be replanted. Varieties and hybrids should be increased by grafting.
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J. nigra |
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VARIETIES
- J. regia (English or Persian Walnut) & var. laciniata, pendula, praeparturiens;
- J. nigra (Black Walnut);
- J. cinerea (Butternut);
- J. Sieboldiana (Japanese Walnut) & var. cordiformis
- J. cathayensis (Chinese Walnut).
