Grafting is uniting a scion or 17 part of a branch of one plant upon the root, branch, or stem of another.

Grafting is a difficult mode of multiplying an individual, because it is requisite so to fit the scion to the stock, that some portion of their alburnums and inner barks must coincide, otherwise the requisite circulation of the sap is prevented. No graft will succeed if not immediately grafted upon a nearly kindred stock. I say immediately, because it is possible that by grafting on the most dissimilar species on which it will take, and then moving it with some of the stock attached, to another stock still more remotely allied, that a graft may be made to succeed though supplied with sap from roots of a very dissimilar species. Thus some pear scions can hardly be made to unite with a quince stock; but if they be grafted upon a young shoot and afterwards inserted in a quince stock, they grow as freely as if inserted in a seedling pear stock.

The reason for this unusual difficulty in the way of uniting kindred species, arises from one or more of these causes. First, the sap flowing at discordant periods. Secondly, the proper juices being dissimilar. Or thirdly, the sap vessels being of inappropriate calibre.

Grafting is employed, first, to multiply any desired variety or species; secondly, to accelerate its fruitfulness, as when the shoot of a two year old apple seedling is grafted upon a stock of six years' growth, it will arrive at fruitfulness much sooner than one left on the parent stem; thirdly, to improve the quality of the fruit by having a more abundant supply of sap: and fourthly, to renew the productiveness of stocks from which previous kinds had failed.

The best modes of grafting are thus described by Dr. Lindley in his admirable Theory of Horticulture: - "Whip grafting is the commonest kind; it is performed by heading down a stock, then paring one side of it bare for the space of an inch or so, and cutting down obliquely at the upper end of the pared part, towards the pith; the scion is levelled obliquely to a length corresponding with the pared surface of the stock, and an incision is made into it near the upper end of the wound obliquely upwards so as to form a ' tongue,' which is forced into the corresponding wound in the stock; care is then taken that the bark of the scion is exactly adjusted to that of the stock, and the two are bound firmly together.

"Here the mere contact of the two enables the sap flowing upwards through the stock to sustain the life of the scion until the latter can develop its buds, which then send downwards their wood; at the same time the cellular system of the parts in contact unites by granulations, and when the wood descends it passes through the cellular deposit, and holds the whole together.

"The use of ' tongue-ing' is merely to steady the scion and to prevent its slipping. The advantage of this mode of grafting is the quickness with which it may be performed; the disadvantage is, that the surfaces applied to each other, are much smaller than can be secured by other means.

"It is, however, a great improvement upon the old crown grafting, still employed in the rude unskilful practice of some continental gardeners, but expelled from Great Britain; which consists of nothing more than heading down a stock with an exactly horizontal cut, and splitting it through the middle, into which is forced the end of a scion cut into the form of a wedge, when the whole are bound together. In this method the split in the stock can hardly be made to heal without great care; the union between the edges of the scion and those of the stock is very imperfect, because the bark of the former necessarily lies upon the wood of the latter, except just at the sides: and from the impossibility of bringing the two barks in contact, neither the ascending nor descending currents of sap are able freely to intermingle. This plan is much improved by cutting out the stock into the form of a wedge, instead of splitting; it may, however, be advantageously employed for such plants as Cactaceae; the parts of which, owing to their succulence, readily form a union with each other.

Fig. 62.

Fig. 63.

"A far better method than whip grafting, but more tedious, is saddle grafting, in which the stock is pared obliquely on both sides till it becomes an inverted wedge, and the scion is slit up the centre, when its sides are pared down till they fit the sides of the stock. In this method the greatest possible quantity of surface is brought into contact, and the parts are mutually so adjusted, that the ascending sap is freely received from the stock by the scion, while at the same time, the descending sap can flow freely from the scion into the stock. Mr. Knight, in describing this mode of operating, has the following observations:

"The graft first begins its efforts to unite itself to the stock just at the period when the formation of a new internal layer of bark commences in the spring, and the fluid which generates this layer of bark, and which also feeds the inserted graft, radiates in every direction from the vicinity of the medulla to the external surface of the alburnum.

"The graft is of course most advantageously placed when it presents the largest surface to receive such fluid, and when the fluid itself is made to deviate least from its natural course. This takes place most efficiently when, (as in this saddle grafting) a graft of nearly-equal size with the stock is divided at its base and made to stand astride the stock, and when the two divisions of the graft are pared extremely thin, at and near their lower extremities, so that they may be brought into close contact with the stock (from which but little bark or wood should be pared off) by the ligature." - Hort. Trans. 147.

To execute saddle grafting properly, the scion and stock should be of equal size; and where that cannot be, a second method, in which the scion may be much smaller than the stock, has been described by the same great gardener.

This is practised upon small stocks almost exclusively in Herefordshire; but it is never attempted till the usual season of grafting is past, and till the bark is readily detached from the alburnum. The head of the stock is then taken off, by a single stroke of the knife, obliquely, so that the incision commences about the width of the diameter of the stock, below the point where the medulla appears in the section, and ends as much above it upon the opposite side. The scion, or graft, which should not exceed in diameter half that of the 6tock, is then to be divided longitudinally, about two inches upwards from its lower end, into two unequal divisions, by passing the knife upwards just in contact with one side of the medulla. The stronger division of the graft is then to be pared thin at its lower extremity, and introduced, as in crown grafting, between the bark and wood of the stock; and the more slender division is fitted to the stock upon the opposite side.

Fig. 64.

Fig. 65.

"The graft, consequently, stands astride the stock, to which it attaches itself firmly upon each side, and which it covers completely in a single season. Grafts of the apple and pear rarely ever fail in this method of grafting, which may be practised with equal success with young wood in July, as soon as it has become moderately firm and mature." - Theory of Horticulture.

The other modes of grafting require no description, but will be best understood by a reference to the following sketches.

Cleft Grafting. Fig. 66.

Side Grafting. Fig. 67.

Chink or Shoulder Grafting. Fig. 68.

Root Grafting. Fig. 69.

By whatever mode the operation be performed, the essentials for success are, 1. That the same parts of the stock and scion should he brought into contact as much as possible - bark to bark, and alburnum to alburnum. 2. That as the nourishment has to be afforded to the graft from the alburnum of the stock with which it is brought in contact, this should not be exposed to the air for one minute longer than is necessary to insert the previously prepared graft, for if the surface becomes dry in the slightest degree, vegetation on that part is permanently destroyed; and thirdly, that the air and wet should be excluded after the scion has been inserted, otherwise the dryness of the parts, or the dilution of the sap, will prevent the union. To effect the desired exclusion, the entire wound must be inclosed with grafting clay or grafting wax, the best recipes for which are these: -

Grafting Clay is best made of two parts cow-dung; three parts common clay; and one part awns or beards of barley, kneaded together thoroughly.

Grafting Wax

Moist bast is usually employed for closing the wound of the stock, but it is far preferable to use worsted, 3nd over this a coating of the grafting wax, made according to the following recipe: -

Burgundy pitch.....1 oz.

Common pitch.....4

Yellow wax......4

Tallow or lard.....2

Peg Grafting, or Te-rebration. Fig. 70.

Nitre (carbonate of potash, powdered).....1

The same composition spread upon slips of linen makes Grafting Plaster, frequently used by amateur budders.