66. When the stocks to be grafted upon are strong, or perhaps branches of large trees, cleft grafting is often re sorted to. The head of the stock or branch, (which we may suppose to be two or three inches in diameter,) is first cut off obliquely, and then the sloped part is cut over ho rizontally near the middle of the slope ; a cleft, nearly two inches long, is made with a stout knife or thin chisel in the crown downwards, at right angles to the sloped part, taking care not to divide the pith. This cleft is kept open with the knife. (Plate CCCIX. Fig. 2. a.) The graft has its extremity for about an inch and a half cut into the form of a wedge, (Fig. 2. b.); it is left about the eighth of an inch thick on the outer or bark side, and is brought to a fine edge on the inside. It is then inserted into the open ing prepared for it ; and the knife being withdrawn, the stock closes firmly upon it. A circular incision is now made in the bark of the stock at the base of the wedge, to the extent of three parts of the circumference of the stock; by this means a shoulder can be formed on each side of the cleft.
67. Old stocks are sometimes grafted in another way, called grafting in the bark- or rind, or crown grafting. The head of the stock or thick branch is cut off horizontally ; a perpendicular slit is made as in budding, (to be presently described) ; a narrow ivory folder, or a silver fruit-knife, is thrust down between the wood and the bark, at the places where the grafts are to be inserted. The graft is cut, at the distance of an inch and a half from its extremi ty, circularly through the bark, not deeper than the bark on one side, but fully half way through, or beyond the pith, on the other. The cut portion is then sliced away ; the end of the graft is pointed, being sloped a little to the point on the outside, but left straight on the inside. A shoulder is likewise left, to rest on the bark of the stock. The grafts arc then inserted into the openings made by the ivory folder ; and either three or four grafts are inserted on a crown, according to its size. This mode cannot be practised till the sap be in full motion, perhaps in the end of March, as till then the bark cannot easily be raised from the wood. When the grafts are placed on old trunks, they are apt to be drawn from their places by violent winds ; it is proper, therefore, to hind them to stakes for the space of perhaps two years, when they will have acquired a suffi cient hold of the stock.
68. Saddle grafting consists in cutting the top of the stock into a wedge-like form, and in making a correspond ing angular notch in the bottom of the graft, to fit the wedge like a saddle. It is a mode sometimes adopted in the grafting of orange trees.
69. Side grafting is merely tongue grafting, performed in the side ul a branch, or in the body of a stock, without heading down. The bark, and a little of the wood, are
sloped off for the space of an inch and a half, or two inches ; a slit is then made downwards, and the graft is cut to fit the part, with a tongue for the slit, (Plate CCCIX. Fig. 3.) ; the parts, being properly joined, are tied close, and clayed over. This mode is sometimes employed for supplying vacancies on the lower parts of full grown fruit trees. It cannot properly be performed till the sap is in action, or till about the middle of March.
70. Grafting by approach, marching, or ablactation, as the older horticulturists termed it, is practised on some kinds of fruit trees, chiefly tender, such as oranges, lemons, pomegranates, and mulberries, and on several ornamental trees which do not readily succeed by the ordinary means, such as myrtles, jasmines, andrachnes, and some rare spe cies of oaks, firs, and pines. \Valnut trees are sometimes also increased in this way. The principle is, that the graft shall continue to have a degree of attachment to the parent plant sufficient to keep it alive, until such time as its bark shall have become united to the bark of the stock which is approached to it. The stock is often planted in a pot (Plate CCCIX. Fig. 4. a.) at least a year before, and is brought close to the tree or shrub to be grafted on it, (Fig. 4. b.); if too low, it is raised on a slight stage to the required height. Where the tree is strong, the pot is sometimes fixed upon one of the branches of the tree. The opera tion of inarching is seldom performed before the middle of April, or the beginning of May. When it can be accom plished, tongue grafting is even in this way advisable. In four or five months the Marched graft is generally found to be fairly united to the stock ; the head of the stock is then cut off; but the graft is not separated from the parent plant till nearly a year has elapsed. , Sometimes, for sake of curiosity, branches of contiguous trees are joined by ap proach-grafting. To make this experiment succeed, it is necessary to fix the branches to poles, to prevent wind waving ; and indeed this caution is in general necessary in all kinds of Marching practised in the open air.
71. Recourse is sometimes had to either for curiosity, or on account of seedling stocks being scarce. A piece of the root of a tree of the same genus, well fur nished with fibres, is selected, and a graft placed on it, tied and clayed in the ordinary way. Thus united, they are set with care in a trench in the ground, the joining being co vered, but the top of the graft being left two inches above ground. Some gardeners have thought that in this way the plant must preserve a nearer resemblance to the parent tree ; but Abercrombie remarks, that though it is an expe ditious way of obtaining a new plant, such a graft cannot be materially different from a cutting or layer.