Fig. 87. Cion for bark-grafting
Double-grafting.—Grafting upon a grafted tree is known as double-grafting or double-working. It is employed for the purpose of growing a variety upon an uncongenial root or of securing a straight and vigorous stock for a weak and poor grower. Some sorts of pears do not unite well with the quince, and if it is desired to secure dwarfs of these varieties, some variety which unites readily with the quince must first be put upon it. The Angouleme takes well to the quince, and upon Angouleme dwarfs the Seckel and some other varieties are often worked. The last cion is usually set after the first one has grown one season, although both may be set at the same time. Double-grafting for the purpose of securing a better growth is often practiced. The Canada Red apple, for instance, is such a poor grower that it is often stem-worked or top-worked upon the Northern Spy or some other strong stock. The Winter Nelis and the Josephine de Malines pears are often double-worked for the same reason.
Cutting-grafting.—Cuttage and graftage are combined in various ways. Cuttings of plants which root with difficulty are sometimes grafted upon those which root easily. When the plants are transplanted, the following autumn or spring, the nurse or stock can be removed, the cion having taken root. Root-grafting with a long cion, described on a previous page (78), is virtually a grafting of cuttings. In other cases, union with an uncongenial stock is facilitated by allowing the cion to project downwards beyond the point of union and to stand in the soil or moss or a dish of water. [Fig. 88] is a good illustration of the practice. The cion extends into the soil nearly as far as the root itself. After union has taken place, the lower part of the cion is removed. This method can be used for some magnolias, mulberries, birches, and many other plants of which some kinds root with more or less difficulty. Bottle-grafting, described in most of the books, is essentially this method, modified by letting the end of the cion drop into a bottle of water. Sometimes a portion of the bandage is allowed to hang in water, to keep the cion fresh until the parts join.
Fig. 88. Cutting-grafting.
Inarching.—Inarching or grafting by approach is the process of grafting contiguous plants or branches while the parts are both attached to their own roots. When the parts are united, one of them is severed from its root. [Fig. 89] explains the operation. In this case, the larger plant is designed for the stock. When the smaller plant has united, it is cut off just below the union and it thenceforth grows upon the other plant. Limbs of contiguous trees are sometimes grafted in this way. It is the process employed by nature in what is called natural grafting. Grape-vines are often inarched. A thrifty young branch may be inarched into the stem of a fruit upon the same tree, thus supplying the fruit with additional food and causing it to grow larger than it might if undisturbed.
To join the parts, it is only necessary to remove the barks between the stock and cion and then tie the two together snugly. If out-doors, the junction should be waxed over; and it is then necessary, also, to secure the branches in such manner that the wind cannot loosen them. The parts are sometimes joined by a tongue, after the manner of a whip-graft, but this is rarely necessary. Oranges and camelias were often propagated by inarching in the old practice, but this work is now much more easily done by the veneer-graft.
Grafting-waxes.—There are great numbers of recipes for waxes or mastics for protecting grafts and covering wounds upon trees. In this country the resin and beeswax waxes are most used, although some of the alcoholic waxes are popular in some regions. In Europe, many clay and pitch waxes are in common use. For most purposes, the wax No. 1 in the following list will be found one of the best, especially for applying by the hand. In making the resin and beeswax waxes, the materials are first broken up finely and melted together. When thoroughly melted, the liquid is poured into a pail or tub of cold water. It soon becomes hard enough to handle, and it is then pulled and worked over until it becomes tough or “gets a grain,” at which stage it becomes the color of very light-colored manilla paper. When wax is applied by hand, the hands must be well greased. Hard tallow is the best material for this purpose. In top-grafting large trees it is well to carry a supply of tallow when waxing by smearing the backs of the hands before entering the tree.