The theoretical objections to root grafts have yielded to sound philosophy, based on and supported by practical observation. The very many advantages of this more economical and convenient and agreeable process, will necessarily sustain root-grafting in this fast age, when so many millions of trees are needed for the rapidly extending wants of this nation of tree planters. We may, however, consider some of the practical objections which have been brought forward against this plan of multiplying the apple. In our very changeable climate, and particularly in the North-west, upon the prairies, the cold of winter often supervenes with great suddenness, after the young trees have made a prolonged and vigorous growth in the fertile soil, and produces terrible devastation among those that are there exposed, without protection of any kind, to the rude blasts of the storm-king: in a less degree, injury is very frequent with many such late-growing kinds, at the first access of a severe frost; this is manifested in the bursting of the bark near the base of the stem. The same thing is not so often seen in the same varieties, when they have been budded or stock grafted a foot or more from the ground upon hardy seedling stocks, hence judicious propagators have selected the "tender" varieties for this kind of working, and confine their root-grafting to those less liable to the injury. There are other varieties which do not readily and promptly form a strong upright growth, so as to be profitable trees to the nurseryman if root grafted; these are selected for stock working, either on strong seedlings, or upon hardy upright sorts that have been root grafted for the purpose of being thus double-worked. This plan has been pursued to a limited extent only, but its advantages in the production of good trees of the slender growing varieties, begin to be appreciated, and as the demand increases, our intelligent nurserymen will very soon furnish the requisite supply.
Planting.—When the weather is fine, and the soil in good condition, the root-grafts are to be set out with a dibble, by the line; they should be planted rather deeply, one bud projecting above the surface of the ground. The culture must be thorough, the plants should be kept perfectly clean, but it is questionable whether the growth should be pushed, late in the season; indeed, it is preferable to check the vegetation at mid-summer. For this purpose it has been recommended to cease cultivating the soil, or even to sow the ground with a heavy seeding of oats, so as to check the growth before winter. In good soils, with good culture, the average hight in the rows will be two feet, but there is a great difference in the kinds; some will considerably exceed this hight. Intelligent nurserymen no longer endeavor to have an excessive growth in the first year, and many prefer the bedding plan above alluded to.
Trimming, Pinching, or Heading.—The growth during the first year is generally a single shoot, sometimes two. If there be a second, it should be subordinated by pinching off its extremity, never by trimming it off; indeed, laterals should always be encouraged, and this will be more and more the case, since the demand for low-headed trees is increasing, as the laws of physiology are better understood. A young tree, well furnished with laterals, is always more stocky, and every way better, though not so tall as that which has been drawn up to a single stem. To encourage this condition, some advise the pinching out the terminal bud in the midst of the growing season, which will cause the swelling and subsequent breaking of the lower buds, so as to furnish plenty of laterals. If done later in the season, especially with strong-growing varieties, a branching head may be formed higher up, during the first season, making very pretty trees. This is, however, seldom attempted with root-grafts the first season, though it is very common for collar-grafted trees, and for buds on strong stocks to make a fine branching growth the first year. The second season the trees should all be headed-in, and the laterals spurred-in early in the spring, or in mild weather during the winter, if the scions are wanted. This method of making stocky plants cannot be too highly commended, nor can the opposite plan, of trimming off all the side branches, and even of stripping the leaves from the lower part of the shoots, during the first summer, be too severely condemned.
Stock Grafting has many advocates, and for some varieties this plan is preferable. The union may be effected at any point from the collar upward. Formerly, the place was selected to suit the convenience of the grafter, and many old orchards show very plainly where they were worked, the stock or the scion having overgrown, and it is very curious that some varieties may be indicated as good feeders of the stock below them, and the contrary. At present, tree planters are more fastidious, and object to these irregularities in the stems of their trees. They will purchase nothing that shows the point of union above ground, hence the more common use of collar grafting, as it has been called, or the insertion of the scion at or near the surface of the ground. Stocks that have been cultivated one or two years in the nursery row, are selected for this purpose; the earth is removed from them, they are cut off and grafted as they stand, and with their fine strong roots undisturbed, the result of one summer's growth is very satisfactory, making beautiful trees fit for the orchard. Older trees, especially those with straight clean stems, are often grafted standard high, so as to produce a fine salable tree at once, or in one season. This is a very good plan with some of the slender and straggling varieties, such as are called poor growers, and which are unprofitable to the nurseryman when propagated in the usual manner. Grafting or budding upon such stocks is also resorted to very often, when it is desirable at once to furnish large, or salable trees of new varieties.
In grafting upon a large stock, or upon the tops of an old tree, the process called cleft grafting is generally used. Here, as in all forms of this process, the object to be attained, is the co-aptation of the inner bark of both stock and scion. The latter is held in its place by the clasping of the former, and is also covered by some material that is pliant, and which will exclude the air and moisture.
The advantages of stock-grafting are the changing of an old tree from bad to good fruit, which is produced in a few years; it is also applicable to large stocks, and produces an immediate result, making salable trees in one year. It is also desirable for some poor-growing varieties, which are slow in making a tree from the ground; but it has its disadvantages also. The nurseryman must wait until his stocks have been grown one or more years in the nursery, his trees will sometimes be larger than he desires, they will be apt to have the mark of the grafting as a blemish upon the stalk sometimes during the life of the tree; and worse than all, he is restricted to a brief period in the spring, when he is obliged to perform the operation out of doors, and often in very unpleasant weather.
As a result of all the discussions upon this subject, it is found that stock-grafting, whether at the collar or at some distance above the ground, is still practiced, and has many warm advocates, as a better means of making the best trees. The only objections are the greater expense of culture of the stocks, and greater labor in grafting; the limited period at which the work can be performed, and the exposure of the workman during its performance, which is often at a stormy season, and always during a busy portion of the year. The trees too, in the orchard, are often somewhat deformed by an irregularity of growth, and have an enlargement either above or below the union, which is unsightly.
The kind of grafting will depend upon the size of the stocks; splice and whip-grafting on the smaller, and cleft-grafting on the larger ones, must be practiced. The waxing may be done by any of the methods indicated, according to the fancy; but it must always be more thoroughly done in aerial, than in underground grafting, whether this be in the collar or upon sections of the root; in the former the whole of the cut surfaces must be covered, to prevent desiccation by the winds, or the inroads of insects, or of wet from rains.
Wax.—Various combinations of the materials used in the preparation of grafting-wax, have been recommended by different operators. The desideratum