This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
Grafting ligneous or other plants while in a state of active growth is usually termed Herbaceous grafting. The manner of uniting the cion to the stock is very similar, and in many instances the same as grafting with ripe wood. In grafting plants that are in a dormant state, or nearly so, it made but little difference whether both stock and cion were in the same condition of forwardness; we usually, however, prefer to have the cion more backward than the stock; but in herbaceous grafting it is quite necessary that they should be very nearly equal. The union between the stock and cion is to be made by the growing process, which is active in both, at the time the operation is performed. It is not to be supposed that a growing shoot can be severed from, one plant and joined to another without slightly checking growth, but the operation must be performed so quickly that the check will be but momentary, the cion reviving soon after. The green growing shoots of one tree may be transferred to other trees, and made to unite with shoots of a similar age and growth, but not to branches of the pre-ceeding year's growth. One or more leaves should always be left on the cions, and those on the stock but slightly reduced.
Splice or cleft grafting is the usual mode, but in some instances side grafting may be successfully practiced. Fig. 29 shows a mode of side grafting on the young shoots of the oak, fig, maple, and similar trees. The pine, spruce, and similar resinous trees may be successfully grafted with their young and tender shots. The time and manner of performing the operation will be fully given in a future chapter. Nearly all species of herbaceous or succulent plants may be successfully grafted one upon another, provided we keep within certain limits, the same as with woody plants. Red beets may be grafted upon yucca beets, tomatoes upon potatoes, musk-melons upon pumpkins, and so on indefinitely. With all the methods of herbaceous grafting, it is generally necessary to protect the graft from the direct rays of the sun until a union takes place. This shading is to prevent a too rapid evaporation of moisture from the leaves of the cion, which would cause the leaves to wilt before they were enabled to receive any assistance from the stock.