Select varieties of the American sweet chestnut (Castanea Americana) are the best in quality that the writer has tested in Europe, Asia, or America, but the varieties of Japan are much larger and some of the west European sorts are superior in size to any we have yet produced, with the exception of some hybrids, which so far have lost in quality what they have gained in size.
Many things are in favor of rapid advances in chestnut-growing. It is far easier to propagate than the walnuts or hickory-nuts, it comes into bearing earlier, and it seems to find a ready market at paying prices. The chestnut has been one of the leading nuts for home use and marketing for centuries in western Asia, Europe, Japan, and north Africa, and indeed a staple article of food when partially dried. It is also used for boiling, and its meal has varied uses in the culinary department.
The largest chestnuts, approaching in quality our best native varieties, came from Sardis in Asia Minor to the Oriental fairs we visited. But as yet these have not been tested in the United States.
The Japan chestnuts make a much smaller and more compact tree than those of Europe, Asia, or the United
States. The leaves are also smaller. The burs are smaller, but the nuts are larger than any varieties yet introduced. Some of the best varieties of all classes are described in Part II of this book.
The tree and bush species, known as "chinquapins" in the South, bear smaller nuts than the chestnuts and usually grow in bush form not more than three to five feet in height. But the tree species (Castanea pumila) on rich soils, in Arkansas and east Texas, we have known to grow thirty or more feet in height. But on thin land both species are shrubs that throw up numerous suckers or stolons. The dwarf species have been used to some extent as stocks for the Japan and other good varieties. But the habit of suckering is specially objectionable.
All varieties and species grow readily from the nuts kept moist by stratification. But the nuts must be planted as early as the condition of soil will permit, or they will sprout in the box (5. Seed-stratification). If grown from seed, the tap-roots should be cut by running a sharp spade under them or they should be transplanted when one year old, to give a good root system. In grafting we have found the side-graft (85. Packing Away the Grafts) most successful, doing the work in the open air when the buds begin to expand. At the West, if the scions are inserted early they are apt to dry up before active sap-circulation begins. We have had the best success when they were covered with paper sacks (284. Walnut Propagation).
As yet, in the eastern States, grafting has been mainly confined to inserting scions in sprouts on mountain land, where the chestnut or chinquapin are indigenous. Where the Japan varieties have been inserted in this way, they have proven profitable in some cases. But the weeds, sprouts, and danger of fire have proven drawbacks to this system, and systematic orchards are now being started.
The usual plan has been to set out two-year-old seedlings once transplanted and graft them the next spring after they have become well established. By culture early in the season and the use of cover-crops of the legumes later, the grafted varieties soon come into bearing. Clean culture through the season has not given good results, as the exposed earth during the hot period gets too warm for the health of the trees and roots (126. Shading of Orchard Soils).
It is best to plant the native and European varieties in rows thirty feet apart, running north and south. To give an approach to forestry conditions, they may be planted only eighteen feet apart in the rows. The smaller-growing Japan varieties should also have ample space between the rows, not less than twenty-five feet, and may be planted fifteen feet apart in the rows running north and south.
In all parts the chestnut is a dry-land or hill tree. In the West, on high, dry ridges, it is grown up to the 44th parallel, but on rich drift-soil, where corn thrives best, the trees are short-lived and unfruitful. The tree does not seem capable of self-pollination. In no case has the writer known a tree in isolated position to bear nuts. Yet blocks planted with a single variety bear well. Where varieties of different species are intermingled in Europe, the cross-pollination gives hybrids when the nuts are planted. This seems true also in this country, as we now have natural hybrids between the chestnut and chinquapin in the South.
A main trouble in the commercial growing of the chestnut is the attack of the weevil. Growers in Europe and America pour boiling-hot water over the freshly gathered nuts. The covered chestnuts are then stirred to prevent cooking them. Those not perfect, on account of weevil perforation, will float on the top. Treated in this way the nuts are not further troubled with weevil, and keep better when fully dried, and the nuts are more palatable and not so hard and horny as when dried without the scalding.