Winter-killing is a serious evil in the nursery, as by it whole rows and blocks of certain varieties are sometimes destroyed, or very seriously injured. It has been observed to be most marked in its effects upon those sorts of trees that make the most vigorous and sappy growth, and those which continue to grow late in the season. Such varieties have very naturally acquired the epithet of tender especially as orchard trees of the same kinds, even in a bearing state, have been similarly affected; in some sections of the country, these kinds have been thrown out of cultivation. The bark looks shriveled and withered, the twigs seem dry when cut, and resist the knife; when thawed by the fire, or on the return of spring weather, the bark seems loose, and the inner bark, instead of being greenish-white, becomes brown, and the whole tree looks as though it was dead. In old trees, large portions of the bark start from the stem and large limbs, and hang loosely for awhile and then fall off. The buds alone retain their vitality, and upon the return of spring they sometimes succeed in establishing the necessary connection with the soil, and restore the circulation of the sap; the results are the deposit of the usual annular layer of woody matter, which encases the dead portions within, that become like a sequestrum of dead bone in an animal. The best treatment for the trees that have been winter-killed, is to cut them back very severely, in the hope of producing a vigorous wood-growth the next season, to repair the injury.
A partial winter-killing often affects small nursery trees, especially on low and wet, undrained soils; the plants recover, but for years they have a black point in the heart which embraces all of the wood-growth that was affected—all their wood at the period of the disaster. This is enclosed and surrounded by clear, healthy wood; but such trees are not desirable, they are so fragile, as to be easily broken.
The best preventive for winter-killing in the nursery, is to encourage early ripening of the wood, and to drain the land, is one of the best means of producing this effect; another is the cessation of culture at mid-summer, and the sowing of oats very thick at the last cultivation, has been practiced, and, it is thought, with excellent effects. The rank growth absorbs the superfluous moisture, robbing the trees, and afterwards forms a good protective mulch during the winter. The objections to it are, that it encourages the mice, which, by girdling the trees, effectually winter-kills them.
Many nursery and orchard trees often present a black discoloration of the bark, which is quite unsightly, and excites alarm for the health of the tree. This is often caused by trimming at unfavorable periods; in the spring pruning of bearing trees, the large stumps sometimes bleed, but in the nursery trees it arises from cutting them, and especially in the barbarous trimming up, during severely cold weather, when they are frozen.
Injurious Animals and Insects.—The nurseryman sometimes suffers from the depredations of some of the smaller animals, which cause him great annoyance. The mole, though highly recommended by the naturalists as a harmless beast, who is an aid to horticulture by his insectivorous habits, is nevertheless injurious in his ways; for he often makes his run in the seed bed, or along a row of root grafts, and raising them from their stations break their tender rootlets, when the sun and air soon destroy them. Mice, of different kinds, are still more destructive, particularly in the winter, when they will often girdle young trees near the collar, and do much mischief. They also devour many seeds after they have been committed to the ground, particularly those sown in the autumn. For both of these animals, the best preventive is to catch them, which may be done with traps. They may also be poisoned. The young trees may be protected from the mice by keeping them clear of rubbish, that would shelter these animals, and when snow falls, it should be trodden down closely about the trees. Owls and cats will do their share in the destruction also, but they will also take the friendly little birds.
Rabbits are also very apt to bite off young shoots, and to bark trees of larger growth in the nursery, as well as those that have been set out in the orchard. Various methods have been suggested to prevent their injuries. Wrapping the stems with strips of rags or with ropes of hay, was formerly the method practiced by those who wished to save their young trees; the process is tedious and troublesome. A few pieces of corn-stalk have been placed by the stem of the tree and tied to it; this, too, is a troublesome procedure, though, like the others, it is efficacious. A still better plan in this class of preventives, is a half sheet of common brown wrapping paper, made to encircle the stem, like an inverted funnel; this need be fastened only at the top, by a little thin grafting wax applied with a brush at the instant, or the paper may be tied with some common white cotton string. This envelope keeps off the rabbits, and lasts through the winter; the string will decay before the growing season returns, so there is no danger of strangulation. All the other wrappings must be removed, or they will injure the trees and afford harbor for insects. It will be observed that all applications of this class, are adapted only to trees that have a clean hole without branches, but are not suited for those which are made to branch at or near the ground. Besides, in countries where snow abounds, these little marauders are elevated above the wrappings, and have fair play at the unprotected parts of the tree—on this account another class of preventives has been adopted.
These consist in applications that are obnoxious to rabbits, which, being nice feeders, are easily disgusted. White-wash, and white-wash made with tobacco water, soap, whale-oil soap, grease, blood, and especially the dead rabbit itself, freshly killed, have all been used with happy results, in that they have driven these animals to seek their food elsewhere. A very good application, and one that may be used upon a low-branched tree as well as to the smooth clear stem of one that is higher, is blood. This is put on with a swab; a few corn husks tied to a stick, answers very well. Dipping this into the vessel of blood, the swab is struck gently against the stem or the branches, as the case may be, and the fluid is spattered over it. A very little will answer to keep the rabbits away, and the effect will continue all winter, notwithstanding the rains.
Certain insects also prove injurious in the nursery, among these the most numerous are the aphides, which are found upon the roots of some fruit trees, especially the apple. Others of this disagreeable insect appear upon the foliage, among these one of the most disgusting is the one which causes the black curl, on young cherry trees. The pear tree slug, (Selandria cerasi), destroys the foliage of many young trees in the nursery; caterpillars also do their share of mischief. A serious trouble in old nursery grounds, especially where manure is used, is the grub of the May beetles, of which there are several species. These grubs are whitish, nearly as thick as the little finger, with a brownish head. They cut off the young nursery trees at three or four inches below the surface. We have seen two-year old stocks cut in this manner, and the work of destruction was so complete, that the proprietor of the nursery was a long time in attributing it to such an apparently inadequate cause as this sluggish, soft-bodied grub. All of these, with other insects injurious to fruit, will be considered in their appropriate place.
CHAPTER IV
DWARFING
DEFINITION OF—OBJECTS—EARLY FRUITAGE—DEFINITION OF TERMS. DWARFING STOCKS—OTHER MEANS OF DWARFING—DWARFS AND STANDARDS. PYRAMIDS OR CONICAL—ESPALIERS—LAYING BARE THE MAIN ROOTS IN SUMMER, TO DIMINISH THE VIGOR OF THE TREES—REMOVING A PORTION OF THEM—ROOT-PRUNING—TRANSPLANTING—EUROPEAN ESPALIERS AND WALL FRUITS—DU BREUIL'S CORDONS—CROWDING, AS A MEANS OF DWARFING—PINCHING, TWISTING, AND FRACTURE—FIELD'S PEAR HEDGES—OUR CLIMATE DOES NOT REQUIRE THESE MEANS OF TORTURE—FACILITY OF PROTECTION MAY RENDER THEM DESIRABLE—GENERAL INTRODUCTION OF QUINCE-DWARFED PEARS IN THIS COUNTRY—MANY FAILURES—SUCCESS DEPENDS UPON CARE—FRENCH SUCCESS—CHINESE—UNCONGENIAL STOCKS—IMPERFECT UNION—PINCHING—HIGHEST PERFECTION OF THE ART OF HORTICULTURE—EQUALIZE THE FLOW OF SAP—NATURALLY FLOWS TO HIGHER PARTS AT EXPENSE OF LOWER, MAY