This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
A shrub, rarely more than 3 feet in height, forming small thickets, by means of stolons, in sandy barrens. South Atlantic states, westward to Louisiana and Arkansas. Distinguished from C. pumila by larger, oval-lanceolate, mostly obtuse leaves, which are but slightly tomentose beneath, and by its larger nuts, which ripen earlier.
The cultural range of Castanea in America is not well defined, but extends from Florida and Texas to Massachusetts and Wisconsin, and on the Pacific slope. The three species cultivated in America thrive best on dry, rocky or gravelly ridges or silicious uplands, failing on heavy clays and on limestone soils unless deep, dry and rich.
Propagation of species is by seeds. Certain types reproduce their striking characteristics in their seedlings, but varieties are perpetuated by grafting, occasionally by budding. Seeds for planting should be free from insect larvae, and should not be allowed to dry out before planting. They may be planted in drills in fall on deep and well-drained loam, or, to avoid damage by rodents, may be stratified in damp sand until spring. Nuts held in cold storage at 15° F. from October to April have germinated well at Washington, D. C. Young trees destined for removal to orchard should be transplanted in nursery at one year old, to promote symmetrical development of root system. Grafting may be done on any of the species of Castanea, and on some of the oaks, notably the chestnut oak, Quercus Prinos, though the durability of grafts on the oak is questionable. Where the chestnut is indigenous, bearing orchards of improved varieties are quickly secured by cutting down and removing the timber, and grafting the young sprouts which spring up in abundance about the chestnut stumps (Fig. 914). Recently the chinquapin has been similarly used with good success where chestnut does not occur.
Grafting may be by splice method on one-year-old seedling roots; by splice or cleft at crown on two- or three-year trees in place; or by veneer, splice or cleft methods on one- to three-year-old sprouts or branches. Top-working of old trees is uncertain and practised only in special cases. Cions should be dormant, and work may be done at any time after freezing ceases, but in trunk- and branch-grafting best results are secured by most grafters if work is done after leaves begin to unfold. Two- or three-bud scions are preferred. The fitting of cion to cleft or splice and the waxing should be carefully done. If strips of waxed muslin are wrapped about the stubs, the danger of loss by summer cracking of wax is lessened. In cleft-grafting young sprouts or seedlings, the stub should be cut 2 or 3 inches above the departure of a branch, to prevent too deep splitting of cleft. Two or three weeks after growth begins the waxing should be inspected and repaired if cracked. If grafts make rank and brittle growth they should be checked by pinching, and if in exposed situations, tied to stakes to prevent breaking out of cions. Budding is sometimes practised, usually by use of dormant buds inserted in shoots of previous year, when the bark "slips" after growth has begun in spring.
There is a growing conviction in the minds of close observers that certain of the popular varieties, especially Paragon, under certain conditions do not find the American chestnut a congenial stock. In several orchards, Paragon, when grafted on native sprouts, although apparently making a good union at the start, has within eight to ten years developed weakness at the point of union, followed by loss of vigor and death of the top without other apparent cause than lack of congeniality of cion to stock. For this variety, at least, the grafting upon seedling stocks grown from nuts of the variety appears advisable. The chestnut is admirably adapted to ornamental planting, either singly or in groups on suitable soils.
Fig. 914. Chestnut sprouts two years grafted. The cion was inserted where branching begins.
The native species is successfully used as a roadside tree in many sections outside of its natural range. It requires a space of at least 40 feet for development when thus used, the European species 30 feet, and the Japanese 20 feet. If in orchard, the last-mentioned may be planted as close as 20 feet, and thinned when the trees begin to crowd, thus securing several crops of nuts from land otherwise unoccupied.
Planted orchards are yet few in America, most of the extensive commercial efforts having consisted in the grafting of sprouts on rough lands where the American chestnut is indigenous. On such lands no cultivation is attempted, the brambles and undesired sprouts being held in check by occasional cutting in summer,' or by pasturing with sheep. Much care is necessary to protect against damage of the sprouts by fire on such land. Clean cultivation, at least during the first few years, is probably best in planted orchards, although heavy mulching may be found a satisfactory substitute. The Japanese and some of the American varieties of the European species require thinning of the burs on young trees to avoid over-bearing, with its consequent injury to the vitality of the tree.