Fig. 75. Veneer-grafting.
Veneer-grafting is employed mostly from November to March upon potted plants. Stocks which are grown out-doors are potted in the early fall and carried in a cool house or pit. The cion is applied an inch or two above the surface of the soil, and the stock need not be headed back until the cion has united. (See [Fig. 76].) Both dormant and growing cions are used. All plants in full sap must be placed under a frame in the house, in which they can be almost entirely buried with sphagnum, not too wet, and the house must be kept cool and rather moist until the cions are well established. Some species can be transferred to the open border or to nursery rows in the spring, but most plants which are grafted in this way are handled in pots during the following season. Rhododendrons, Japanese maples and many conifers are some of the plants which are multiplied by veneer-grafting. This method, when used with hardy or tender plants, gives a great advantage in much experimental work, because the stock is not at all injured by a failure and can be used over again many times, perhaps even in the same season; the manipulation is simple and easily acquired by inexperienced hands.
Cleft-Grafting.—In cleft-grafting the stock is cut off squarely and split, and into the split a cion with a wedge-shaped base is inserted. It is particularly adapted to large stocks and is the method universally employed for top-grafting old trees. [Fig. 77] represents the operation. The end of the stock, technically called a “stub,” is usually large enough to accommodate two cions, one upon either side. In fact, it is better to use two cions, not only because they double the chances of success but because they hasten the healing of the stub. Cleft-grafting is at best a harsh process, especially upon large limbs, and its evils should be mitigated as much as possible. In common practice, the cion ([Fig. 78]) contains three buds, the lowest one standing just above the wedge portion. This lowest bud is usually entirely covered with wax, but it pushes through without difficulty. In fact, being nearest the source of food and most protected, its chances of living are greater than those of the higher buds. The sides of the cion must be cut smoothly and evenly. A single draw cut on each side with a sharp blade is much better than two or three partial cuts. A good grafter makes a cion by three strokes of the knife, one to cut off the cion and two to shape it. The outer edge of the wedge should be a little thicker than the inner one so that the stock will bind upon it and hold it firm at the point where the union first takes place. These cions are taken in late fall or winter, and kept in the same manner as directed for whip-grafting on pages 77 and 78.
Fig. 76. Veneer-graft.
Fig. 77. Cleft-grafting.