CHAPTER XI.

OF PROPAGATION BY LAYERS AND SUCKERS.

WITH regard to layers, there is little which it is necessary to say regarding them, if what has been stated respecting eyes, leaves, and cuttings, has been rightly understood and well considered. A layer is a branch bent into the earth, and half cut through at the bend, the free portion of the wound being called "a tongue." It is, in fact, a cutting only partially separated from its parent.

The object of the gardener is to induce the layer to emit roots into the earth at the tongue. With this view he twists the shoot half round, so as to injure the wood-vessels; he heads it back so that only a bud or two appears above ground; and, when much nicety is requisite, he places a handful of silver sand round the tongued part; then pressing the earth down, so as to secure the layer, he leaves it without further care. The intention of both tongueing and twisting is to prevent the return of sap from the layer into the main stem, while a small quantity is allowed to rise out of the latter into the former; the effect of this being to compel the returning sap to organize itself externally as roots, instead of passing downwards below the bark as wood. The bending back is to assist in this object, by preventing the expenditure of sap in the formation or rather completion of leaves; and the silver sand is to secure the drainage so necessary to cuttings.

In most cases, this is sufficient; but it must be obvious that the exact manner in which the layering is effected is unimportant, and that it may be varied according to circumstances. Thus, Mr. James Munro describes a successful method of

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PROPAGATION BY LAYERS.

layering brittle-branched plants by simply slitting the shoot at the bend, and inserting a stone at that place (Gardeners' Magazine, ix. 302): and Mr Knight found that, in cases of difficult rooting, the process is facilitated by ringing the shoot just below the tongue, about midsummer, when the leaves upon the layers had acquired their full growth (Hort. Trans., i. 256); by which means he prevented the return of sap further downwards than the point intended to root.

It will sometimes happen that the branch of a plant cannot be conveniently bent downwards into the earth; in such cases, the earth may be elevated to the branch by various contrivances, as is commonly practised by the Chinese. In this no other care is necessary than that required for layers, except to keep the earth surrounding the branch steadily moist.

Suckers are branches naturally thrown up by a plant from its base, when the onward current of growth of the stem is stopped. Where this occurs the onward growth of a plant is arrested, the sap is driven to find new outlets, and adventitious buds (see p. 44) are very likely to be developed; the well-known effect of cutting down a tree is an exemplification of this. Such branches, if they proceed from under ground, sometimes form roots at their base, in which case they are employed as a means of propagation; in the instance of the Pine-apple, they are made use of for the same purpose, although they do not emit roots till they are separated from the parent. Gardeners usually satisfy themselves with taking from their Pine-apple plants such suckers as are produced in consequence of the stoppage of onward growth by the formation of the fruit: but these are few in number, and not at all what the plant is capable of yielding. Instead of throwing away the "stump" of the Pineapple, it should be placed in a damp pit, and exposed to a bottom heat of 90° or thereabouts, when every one of the latent eyes will spring forth, and a crop of young plants be the result. Mr. Alexander Forsyth, an experienced writer upon these subjects, pointed this out some years since in the Gardeners' Magazine (xii. 594); and there can be no doubt that his observations upon the folly of throwing away "stumps" are perfectly correct both in theory and practice.

CHAPTER XII.

OF PROPAGATION BY BUDDING AND GRAFTING.

THESE operations consist in causing an eye or a cutting of one plant to grow upon some other plant, so that the two, by forming an organic union, become a new and compound individual. The eye, in these cases, takes the name of bud, the cutting is called a scion, and the plant upon which they are made to grow is named the stock.

Propagation by eyes and cuttings is, therefore, the same as budding and grafting, with this important difference, that in the one case the fragments of a plant are made to strike root into the inorganic soil, and to grow "on their own bottom," as the saying is, while in the other they adhere permanently to living organic matter. In like manner, the operation of inarching, or causing the branch of one plant to remain attached to its parent, and at the same time to grow upon the branch of another tree, is analogous to layering.

The objects of these operations are manifold. Many plants, such as the Pear and the Apple, will bud or graft freely, but are difficult to strike from cuttings. Species which are naturally delicate become robust when "worked" on robust stocks; and the consequence is a more abundant production of flowers and fruit: thus the more delicate kinds of Vines produce larger and finer grapes when worked upon such vigorous sorts as the Syrian and Nice. The Double Yellow Rose, which so seldom opens its flowers, and which will not grow at all in many situations, is said to blossom abundantly, and grow freely, when worked upon the common China Rose. (Hort. Trans., v. 370.) One plant may be made to bear a

different variety upon every branch, as has been seen with Pelargoniums, Fuchsias, and Cacti. (Gard. Chron., 1844, 119, 213.) The peculiar qualities of some plants can only be preserved by working: this is especially the case with certain kinds of variegated Roses, which retain their gay markings when budded, but become plain if on their own bottom. (Ib. 492.) Fruit may be obtained from seedling plants by these processes much earlier than by any others, the quality of seedling fruittrees may be ascertained in two or three years instead of twenty or thirty, and thus long and objectless expectation may be avoided: indeed, Mr. Knight ascertained that it is possible to transfer the blossom-buds of one plant to another, so as to obtain flowers or fruit from them immediately. He thus fixed on the Wild Rose the flower-buds of Garden Roses, "and these buds, being abundantly supplied with nutriment, afforded much finer roses than they would have done had they retained their natural situation." He repeated many similar experiments upon the Pear and Peach-tree with similar success; but in the case of the Pear, he found that if the buds were inserted earlier than the end of August or beginning of September, they became branches and not flowers.

The modes in which these operations may be practised are exceedingly various, and an abundance of methods (often fanciful) have been devised, for a complete account of which the reader is referred to Thouin's Monographie des Greffes; to the article "Greffe" by the same author, in the Nouveau Cours complet d'Agriculture, &c., edition of 1822; to Loudon's Encyclopædia of Gardening, part ii.; to the Gardeners' Magazine, vol. x. p. 305, and to future pages of the present work.

BUDDING Consists in introducing a bud of one tree, with a portion of bark adhering to it, below the bark of another tree. In order to effect this, a longitudinal incision is made through the bark of the stock down to the wood, and is then crossed at the upper end by a similar cut (Fig. XLIII., a), so that the whole wound resembles the letter T. Then from the scion is pared off a bud with a portion of the bark (Fig. XLIII., b), and

OPERATION OF BUDDING.

305

the latter is pushed below the bark of the stock until the bud is actually upon the naked wood of the stock; the upper lips of the wound in the stock and that of the bud are made to coincide, the whole are fastened down by a ligature, and the operation is complete.

The ligature has usually been of bast, applied wet; but it is apt to become loose. A better material is narrow tape, or narrow adhesive straps, made as directed in a succeeding page (340). White and green worsted are also employed in preference to bast. It is also said that for delicate operations, with green parts, collodion painted over the juncture of the scion and stock, forms an effectual ligature.

Fig. XLIII.
Shield-budding.

By these means we gain the important end of bringing in close contact a considerable surface of young organizing matter. The organization of wood takes place on its exterior, and that of bark on its interior surface, and these are the parts which are applied to each other in the operation of budding; in addition to which the stranger bud finds itself, in its new position, as freely in communication with alimentary matter, or more so, than on its parent branch. Union takes place of the cellular faces, or horizontal system, of the stock and bark of the bud, while the latter, as soon as it begins to grow, sends down organizable matter, out of which wood, or the vertical system, is constructed. In consequence of the horizontal incision, the returning sap of the scion is arrested in its course, and accumulates a little just above the new bud, to which it is gradually supplied as it is required. Sometimes the whole of the wood of the bud below the bark is allowed to remain; and, in that case, contact between the organizing surfaces of the stock and scion does not take place, and the union of the two is much less certain: as it is, however, usually practised with tender shoots before the wood is consolidated, the contact spoken of is of less moment.

X