The native black walnut (Juglans nigra) has a wide distribution in the Northern States. It is one of our largest trees and its lumber is so valuable for gun-stocks, furniture, and other uses, that trees of large size are becoming scarce in every locality. Along streams in the prairie States it was a common tree in the early days of prairie settlement, but most all the trees have been cut latterly for export of the logs to Europe.
The nuts of our native walnut are beyond doubt the largest and best wild ones of the earth, but as yet no move has been made for their improvement. In Europe and Asia the wild walnuts of Armenia, north India, Burmah, Japan, and central Asia are vastly inferior to our best native types. But they have been improved by selection and culture until we have the modern walnuts of commerce.
As found in the prairie States the nuts are more variable than in other parts of the Union observed by the writer. In a few cases varieties are found with relatively thin shell that splits readily and the meat parts from the shell divisions freely. But as yet they all have the peculiar flavor that many like and a few dislike. Burbank, of California,
has proven that the Persian walnut will cross with Juglans nigra and also with the J. Californica of the west coast. In the near future we will probably have crosses with the best European varieties that will combine the good qualities of the two species.
The black walnut grows readily from the nuts if managed properly. In the fall, spread out the nuts without removing the shucks under trees and cover with four inches of leaves. Early in spring plant very shallow, firming the earth by stepping on each covered nut. If to be used for stocks for budding or grafting, the nuts easiest to secure will answer the purpose. But if planted for nut-growing, care should be taken to hunt for the trees bearing the largest and best nuts. In the prairie States groups or local areas of walnut were found in the early days, with relatively thin shell, that have been reproduced by many by planting the nuts. But if scions of select varieties are procurable, it is not difficult to insert them under the bark of thrifty young stocks, as noted in section (284. Walnut Propagation).
It has also been found that scions of Juglans regia will unite well with the wood of young thrifty stocks of our native black walnut, and it increases the hardiness of the former when grown in more trying climates remote from the ocean.