Propagation by means of a slip or scion cut from the parent tree

“Propagation by means of a slip or scion cut from the parent tree and so placed that it will develop adventitious roots we may for convenience speak of as slipping. The cut end of the slip is set in the ground in some cool, moist, shady spot where evaporation is slow and the temperature mild. For delicate slips the shelter of a bell-glass is often necessary in order to insure the requisite moisture in the atmosphere and thus prevent the slip from drying up before it has sent down roots to make good its losses. For greater surety, if the slip has many leaves, most of the lower ones are removed in order to reduce the evaporating surface as much as possible without compromising the plant’s vitality, which resides especially in the upper part. But in many cases these precautions are needless; thus, to propagate the grape-vine, willow, and poplar, it suffices merely to thrust the detached scion into the ground.

“Trees whose wood is soft and well filled with sap are the ones best fitted for slipping; to this class belongs the willow, with its notably tender fiber. On the other hand, wood that is dense and hard gives us sure warning that this mode of propagation will [179]be found very difficult or even impossible. Thus it would invariably fail with the oak, the olive, the box-tree, and a great many more hard-wood trees. Furthermore, slipping offers far less certainty of success than layering, since the layer remains in communication with the parent stock and is thus supplied with nourishment until it has acquired roots of its own, whereas the slip, all such communication being abruptly cut off, is obliged from the outset to rely on its own resources and pass without help through the difficult period of rootlessness. Among fruit-bearers there are scarcely any except the grape-vine, the currant-bush, the quince-tree, and a few varieties of plum and apple trees, that lend themselves to this method of propagation. Among the larger trees the willow and the poplar take root with no difficulty whatever when started from the slip. Finally, a great many ornamental species, herbaceous plants or bushes like the rose, jasmine, and honeysuckle, multiply easily by this method, the usual one adopted with them by the flower-gardener.

“Let us go back now to the very simplest case, the one calling for the fewest precautions. A damp piece of ground on the water’s edge is to be planted with poplars or willows. Toward the end of winter the forester in charge cuts a sufficient number of vigorous young branches as large around as a stout cane or even a man’s fist, or perhaps larger, and from one to four meters long. He removes all the lower twigs, clips the intermediate ones to half their length, and leaves the upper ones intact if the tree [180]is to be pyramid-shaped; otherwise he gives the top a truncate form. Finally the lower end is cut to a point with the hatchet, to make it easier to thrust into the ground. Now the slip is ready for planting, and all that is necessary is to push it well down into the earth by its pointed end and leave it to itself. Without any further attention, if the ground is sufficiently damp, adventitious roots will start, and each of the stakes thus rudely hacked will become a poplar or a willow.

“But other forms of vegetation are far from manifesting this facility in rooting which makes possible the growth of a tree from a stake driven into the ground, it may be with the blow of a club; therefore delicate precautions are necessary for success if these obdurate subjects are to be propagated by slips. Let us take the grape-vine as an example. Its slips for planting are shoots of the same year’s growth. These are tied in a bundle and their cut ends placed in water to soak for a week or more. Why this long immersion of the part that later is to be planted in the ground? Because the outside bark is dry and tough, difficult for tender roots to pierce, especially if the soil is dry. Accordingly the bark is softened by soaking for some time in water; and also, when the slips are taken out of the water, they are lightly scraped where they are to be in the earth, but left untouched where they are to be in the air. In this way the outer layer of bark is removed after being softened in water, and there is so much the less resistance offered to the growing roots; [181]but the inner layers, where the vine’s vital activities go on, are scrupulously spared. The slight wounds inflicted by this scraping, let it be further noted, favor the starting of roots by arresting the sap. After being prepared in this manner the slips are set out. In soil that has been well worked so that the young roots may push downward without hindrance, vertical holes are made with a long iron or wooden dibble, and in each of these holes a slip is inserted to the depth of about half a meter. Fine earth is then sifted into the hole and well rammed down to insure perfect contact with the slip, and the operation is finished.

“Just as the process of layering is facilitated by the formation of a ring-shaped swelling where the descending sap is arrested in its course either by a ligature or by the removal of a ring of bark, so the same artifice can be advantageously employed in propagating by means of slips. Around the shoot selected as slip for the next year’s planting an iron wire is tightly bound; or, instead of this, a ring of bark is cut away. By autumn a swelling will have formed all about the stem, whereupon the shoot is detached and placed in the ground for the winter in order that the swelling may become a little further enlarged and somewhat softened. In the spring the shoot is taken up again, trimmed so that it shall have only four or five buds left, and planted like an ordinary slip. From the ring-shaped swelling caused by the accumulation of sap roots will start.

“All the advantages offered by the ring-shaped swelling may be secured with no expenditure of ingenuity on our part. Take hold of a small branch and pull it down so as to split it off from the main stem. Thus torn away it will bring with it a sort of spur or splinter from the trunk directly under the severed branch. This spur, trimmed with a knife to give it a less ragged outline, will render the same service as the ring-shaped swelling: the descending sap will be stopped in its course at this point, will accumulate, and will foster the growth of adventitious roots.

“Instead of breaking off the branch by tearing it away at its base, one can, with a stroke of the pruning-knife above this base and another below it, cut the older limb bearing this branch so that the latter carries with it a piece of the former. With this piece as a sort of natural bourrelet or swelling, success is rendered more assured than in any other way.

“To conclude, let us say a few words about slipping by means of buds, a kind of planting that uses buds instead of seeds. This method, which requires the nicest care of any, is adopted only in exceptional cases. Let us suppose we have a very few shoots, or only one, from some extremely rare variety of grape-vine, and we wish to obtain from this single shoot the greatest possible number of slips. To this end the shoot is cut into small pieces about five centimeters long, each bearing a bud midway of its length. These pieces are then each split in two lengthwise, and the part with the bud is retained, the other thrown away. Thus prepared, the pieces [183]are planted in fertile soil with the split surface underneath and the bud just peeping out of the earth. But to insure any likelihood of success with this method, certain special conditions not called for in ordinary planting must be observed, as will be readily understood. The delicate slips are arranged with care in an earthen pan or pot, and covered with a bell-glass to assure them a moist and warm atmosphere. After roots have started the slips are transplanted, each being placed in a separate pot where it gains strength and awaits the proper time for planting in the ground.”