THE LAYERING

Field, Forest and Farm by Jean-Henri Fabre, is part of the HackerNoon Books Series. You can jump to any chapter in this book here. LAYERING

CHAPTER XXXV. LAYERING

“Some plants, and among them the pink, send out from the base of the mother stalk straight, pliant shoots which can be used for obtaining so many new plants. These shoots are bedded by being bent elbow-wise and having the angle stuck into the ground and fastened there with a crotch; then the end is raised upright and held so by means of a stake. Sooner or later the buried elbow sends down adventitious roots, but until then nourishment is drawn from the parent stock. When the buried parts have sent down enough roots, the connections are cut between the old plant and the new ones, and each of these latter, set out by itself, is thenceforth a distinct plant. This operation is called layering, and the several shoots used in obtaining new plants are called layers.

Layering

“Let us now put into practice the method we have just been studying in theory. In a vineyard, we will suppose, a number of the vines have died from some cause or other, and it is necessary to replace them. Layering offers us the readiest means and will occasion least delay to the harvest. Near the place occupied by the dead vine we select a stock provided [171]with a vigorous shoot of sufficient length and conveniently situated. Then we dig down where the old vine stands and pull up all of the lifeless stalk as well as the roots, since these are seats of decay that might infect the whole neighborhood. Finally, in the soil thus stirred we dig a ditch two or three decimeters deep, and in this we lay the shoot we have selected, taking care in bending it down not to break or splinter it. The part thus put into the ground is then covered with a tolerably thick layer of earth, and on this, to complete the filling of the ditch, is thrown a basketful of manure. The tip of the shoot is raised upright, tied to a stake, and trimmed in such a manner as to retain only two eyes or buds above ground. As to the eyes on the part extending from the mother stem to the point where the shoot plunges into the ground, they are nipped off because they would needlessly appropriate a part of the sap. This operation is called vine-layering, and the shoot bent down and placed in the ground we speak of as a vine-layer. The best time for this work is the beginning of winter, because the long rest enjoyed by the shoot in the ground throughout the season when vegetation slumbers disposes it to sprout with more vigor upon the renewal of sap-circulation in the spring.

“Let us now watch the behavior of the partly buried vine-shoot. If it had remained all in the open air, it would have borne fruit; it would have had its three or four bunches of grapes. Why should it not do so under the conditions imposed by the vine-dresser, [172]conditions that have altered nothing in its relations to the mother stem? It still remains in uninterrupted communication with the vine that sustains it; it receives its share of ascending sap drawn from the soil by the roots of this vine; the buds remaining to it will develop leaves which, with the help of sunlight, will convert this crude sap into elaborated sap; in short, it lacks nothing to enable it to function almost as it would have done had it not been partly buried. And in fact the vine-layer does bear that same year; if well cared for, it bears several bunches of grapes. So the proverb says: The vine-layer pays its owner from the very first year. Meanwhile, acted on by the coolness and moisture of the soil and the stimulus of fertilization, it puts forth adventitious roots where it has been placed underground, and these roots grow in number and vigor until the time comes when they suffice to nourish the young vine without the help of the mother stem. It is in the third year that the rooting is far enough advanced for the young offshoot’s independent existence. Weaning is then undertaken, and the nursling is deprived of its nurse; that is to say, a stroke of the pruning-knife close to the ground and on the side toward the parent stock separates the latter from the vine-layer, which becomes henceforth self-supporting.

“With its long shoots so near the ground the vine offers every convenience for carrying out the operation just described; but as a general rule shrubs and trees are far less favorably situated: their branches [173]are not long enough or flexible enough or (a prime essential) near enough to the ground to be bent down and laid in the trench dug for receiving the layer. How is this difficulty to be overcome? The way is very simple. We have already observed the effect of cutting back; we know that a stem cut back, that is to say cut off close to the ground, develops around the border of its wound numerous adventitious buds which grow into so many shoots. They are precisely the sort of shoots we need, long, flexible, and starting from the level of the ground. Each of them, if treated as a layer, partly buried in a trench where it is fixed with a crotch, and held, above ground, in a vertical position by means of a prop, takes root sooner or later according to its species, and can then be transferred as an independent plant to any desired spot. Such is the simple method known both as layering and as arching, because it is essentially the same as ordinary layering and at the same time necessitates the bending of the young shoot so as to describe an arch.

“The following method dispenses with this bending, which is impracticable when the wood is too brittle. In the spring the stalk or trunk that is to furnish the layers is cut back. All around this cross-section young shoots soon make their appearance, after which it is only necessary to wait until they are long enough but have not yet lost their tenderness, a state most conducive to the growth of adventitious buds; then the parent trunk is earthed up, or in other words light soil is heaped all about the [174]stump so as to cover the lower part of each shoot. The earth is piled up in the shape of a truncated cone with a cup-shaped hollow at the top to receive water from time to time and thus maintain the necessary degree of moisture and coolness. Kept damp and cool in this manner, the young shoots will before long send down adventitious roots, and the following year there will be a cluster of rooted plants that can easily be detached with a knife. That is what is called layering by earthing up or by sprouting.

“If it is found undesirable to cut back the parent stem in order to obtain shoots for layering, and if at the same time the shoot that we wish to root is too high to be bent down and inserted in the ground, the following expedient may be employed. A flower-pot broken in two lengthwise or a leaden cornucopia is hung on the tree, and the branch to be rooted is placed lengthwise in the pot or cornucopia. The pot is then filled with mold or moss kept damp by frequent watering, and the result, sooner or later, is the growth of adventitious roots. When these are suitably developed, gradual weaning is next in order; that is to say, underneath the pot a slight cut is made, and this is deepened day by day. The end here in view is to accustom the layer little by little to do without the mother stem and support itself. At last the separation is complete. This gradual weaning is no less advantageous when the layers are placed in the ground: it assures the success of the operation.[175]

“If the wood is tender, adventitious roots spring without difficulty from the interred part, and the methods already described suffice for the success of the layering; but woods of dense structure are more or less obstinate about taking root, and might remain in the ground indefinitely without yielding. In such cases our art must intervene, based on the plant’s manner of living. Let us recall the effect of a band drawn tightly about a stalk or trunk. Above this line of strangulation the descending sap accumulates more and more, since it can no longer continue on its course between the wood and the bark, this latter being compressed by the ligature. It accumulates and produces a ring-shaped swelling where the plant tries to discharge on the outside the superabundance of matter arrested in its passage. Let this protuberance be heaped about with fresh earth, and adventitious roots will speedily be developed to allow the sap to continue its descent. A tiny streamlet, running free, follows its channel without effort and without any undermining of obstacles. But if we obstruct its passage the accumulating body of water will gain power to open new vents for itself through the dam. Sap does likewise. Circulating freely in its natural channel, it is not diverted from its course by any allurements on its way; and unless the conditions present in wood and bark favor the growth of new roots, no sap will be expended for this purpose. But if its usual passage is barred, the sap devotes its energies to the formation of adventitious roots in order that [176]it may, through them, resume its interrupted course. A like result follows if a ring of bark is removed from the buried part of the branch or shoot that we wish to take root. The arrested sap produces a ring-shaped swelling on the upper edge of the wound, and from this swelling spring roots.

“Now let us apply these theoretical principles. If the wood is compact and for that reason rebels against the laws of simple layering, we will take a piece of wire and strangle (that is the word) the branch we are operating upon; that is to say, we will bind it tight, but without breaking the bark. The compression should be made just below a bud or eye, and about midway of the part that is to be underground. This process is called layering by strangulation.

“Or again, still midway of the part to be bedded in the earth, and immediately under a bud, we cut the bark all around the branch without injuring the wood; a second incision is made a centimeter and a half lower down; then tearing off the strip of bark between the two circumcisions, we remove it all in one piece. This method is known as annular incision from the ring of bark thus taken away.

“Or as a third expedient, still midway of the part to be bedded in the trench, we make with a sharp instrument an oblique incision from below upward, cutting into the wood as far as the marrow. In this way we are enabled to raise a tongue comprising half the thickness of the shoot, and this tongue is held in its lifted position by a small pebble inserted in the [177]slit. This is what we call a Y-shaped incision, because the raised tongue forms with the rest of the stem an opening like that between the two branches of the letter Y. Through the half that remains intact communication with the mother stem is maintained and the needed share of crude sap is received, while from the cut and upraised half adventitious roots are put forth because the course of the descending sap is arrested there.

“In order to bring into contact with the damp soil a greater extent of wounded fiber fit for putting forth adventitious roots, it is customary to split the upraised tongue in two and keep the two parts gaping by interposing a small pebble. This method of double incision is used for trees that offer the greatest resistance to successful layering.

“To sum up, all these methods and others derived from them have for their object the fostering of adventitious roots by arresting the course of the descending sap at a certain point beneath the soil.”

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