American Pomology. Apples

PROPAGATION.—SECTION I

ALL GROWTH IS DEPENDANT UPON THE DEVELOPMENT OF CELLS—THE SEED AND THE BUD; THEIR RESEMBLANCE—THE INDIVIDUALITY OF BUDS—THE BASIS OF ALL PROPAGATION—BUDS ARE DEVELOPED INTO TWIGS; HAVE POWER OF EMITTING ROOTS—IMPORTANCE OF THE STUDY OF CELL-GROWTH—BY CUTTINGS: PREPARATION AND SELECTION—HEEL-CUTTINGS—SOFT WOOD—HARD WOOD—SEASONS FOR EACH—FALL PLANTING—THE CALLUS, OR DEVELOPMENT OF CELL-GROWTH—BOTTOM HEAT; WHY BENEFICIAL—WHY SPRING CUTTINGS FAIL—STIMULUS OF LIGHT UPON THE BUDS, CAUSES THEM TO EXPAND, AND THE LEAVES EVAPORATE TOO FREELY—ROOT CUTTINGS; DIFFERENT FRUITS THUS PROPAGATED—BY SUCKERS: OBJECTIONS TO ANSWERED—SUCKER ORCHARDS; BEAR EARLY—SUCKER TREES APT TO SUCKER AGAIN—BY LAYERS: A NATURAL METHOD—HOW PERFORMED—THE RASPBERRY AND THE GRAPE—ILLUSTRATIONS OF NATURAL AND ARTIFICIAL METHODS—QUINCE STOCKS—ADJUVANTS TO LAYERING, NOTCHING, ETC—BY SEEDS: HOW IT DIFFERS FROM THE OTHERS—APPLE SEEDLINGS—THEIR TREATMENT, SEPARATING, AND PREPARING THE SEED—APPARATUS—SPROUTING—SOWING—CULTIVATION—SEEDLINGS—TREATMENT—SORTING—PACKING.

All propagation of plants must depend upon the development of seeds or of buds, and all will arise from the growth and extension of cells. The seed and the bud are much more nearly related than a casual observer would at first sight suppose. The early phylologists thought they discovered that in the seed was enwrapped the image of the future tree—a dissection of the seed would appear to demonstrate this. It is composed of separate parts which are capable of being developed into the root, stem, and appendages, but they have yet to be so developed; the several parts that we find in the seed are merely the representative parts. But the seed has the future of the tree within itself, it has certain qualities of the future tree impressed upon it in its primary organization, within the capsule of the fruit of the parent plant, so that in a higher sense the image of the future tree does exist within the seed. Within the bud, still more plainly and more distinctly visible, is the future tree manifest, and we may produce a tree from a bud as certainly as we do from a seed. Subjected to circumstances favorable for growth, the bud, as well as the seed, will emit roots, will form its stem, branches and appendages, and will become a tree; differing from the product of the seed only in this, that in the latter the resulting organism constitutes a new individual which may vary somewhat from its parent, in the former it is only a new development of a part of a previously existing organization. The similarity existing between the two is exceedingly close, and is a matter of great importance in horticultural operations. Dr. Lindley, in the Gardener's Chronicle, says very truly, that "every bud of a tree is an individual vegetable, and a tree, therefore, is a family or swarm of individual plants, like the polype with its young growing out of its sides, or like the branching cells of the coral insect." Similar opinions, more or less modified, have been expressed by subsequent physiologists, and are familiar to men of science in every country and, we may add, are also universally accepted as true by all who claim a right to express an opinion upon the subject.—Men of science recognize the individuality of buds.—Nobody doubts the individuality of buds.—In a gardening aspect, the individuality of buds is the cardinal point upon which some of our most important operations turn; such, for example, as all modes of propagation whatever, except by seed. If this be not fully understood, there is no possible explanation of the reasons why certain results are sure to follow the attachment of a bud, or the insertion of a graft, or the planting of a cutting, or the bending of a layer, or the approach of a scion, or the setting of an eye—our six great forms of artificial multiplication. In his Elements of Botany, the same writer says: "An embryo is a young plant produced by the agency of the sexes, and developed within a seed—a leaf bud is a young plant, produced without the agency of the sexes, enclosed within the rudimentary leaves called scales, and developed on a stem." "An embryo propagates the species, leaf-buds propagate the individual." He shows each to be "a young plant developing itself upwards, downwards and horizontally, into stem, root, and medullary system."

Dr. Schleiden thus beautifully expresses his views of their individuality: "Now the bud essentially is nothing more than a repetition of the plant on which it is formed. The foundation of a new plant consists equally of a stem and leaves, and the sole distinction is that the stem becomes intimately blended at its base with the mother plant in its growth, and has no free radical extremity like that exhibited by a plant developed from a seed. However, this distinction is not so great as at the first glance it appears. Every plant of high organization possesses the power of shooting out adventitious roots from its stem, under the favoring influences of moisture; and very frequently, even plants that have been raised from seed, are forced to content themselves with such adventitious roots, since it is the nature of many plants, for instance the grasses, never to develop their proper root, although the radicle is actually present. We are, it is true, accustomed to look upon the matter as though the buds must always be developed into twigs and branches, on and in connection with the plant itself; and thus in common life, we regard them as parts of a plant, and not as independent individuals, which they are in fact, although they, like children who remain in their paternal home, retain the closest connection with the plant on which they were produced. That they are at least capable of becoming independent plants, is shown by an experiment frequently successful when the necessary care is taken, namely the breaking off and sowing of the buds of our forest trees. The well-known garden operations of grafting and budding are also examples of this, and layering only differs from the sowing of the buds, in that the buds on the layers are allowed to acquire a certain degree of maturity before they are separated from the parent plant. All here depends upon the facility with which these bud plants root as it is called, that is develop adventitious roots, when they are brought in contact with moist earth. * * * Nature herself very often makes use of this method to multiply certain plants in incalculable numbers. In a few cases, the process resembles the artificial sowing of buds, as when the plant spontaneously throws off the perfect buds at a certain period; an instance of this is afforded by some of our garden Lilies, which throw off the little bulb-like buds which appear in the axils of the lower leaves. The more common mode of proceeding is as follows: Those buds which have been formed near the surface of the soil, grow up into shoots provided with leaves; but the shoots are long, slender and delicate, the leaves too are stunted into little scales; in their axils, however, they develop strong buds, which either in the same or in the following year take root, and the slender shoot connecting them with the parent plant, dying and decaying, they become free independent plants. In this manner the strawberry soon covers a neglected garden."12

Upon the development of a cell in any living tissue, and its power of reproducing other cells, and upon its function of communicating by endosmosis and exosmosis with other like cells, depend all our success in propagating vegetables, whether from seeds or buds, and parts containing these. We must study the circumstances that favor the development of cells, if we would be successful in propagating plants. Each bud being considered an individual, and capable, under favorable circumstances, of taking on a separate existence, we can multiply any individual variety indefinitely, and be sure of having the same qualities of foliage and fruit that we admire in the original, and that we may desire to propagate. This applies equally to a group of buds, as in cuttings, grafts and layers, etc.; but, more wonderful still, there are cells capable of developing buds where none existed before, and even in tissues or parts of a plant where we do not usually find buds—hence we have a mode of propagation of many woody plants, by root cuttings, and by leaves, and even parts of leaves.

Propagation by Cuttings.—Many fruits are multiplied by this means. Healthy shoots of the previous year's growth are usually selected and taken when the parent is in a dormant state, or still better, when it is approaching this condition. Sometimes a small portion of the previous year's growth is left with the cutting, making a sort of heel; when this is not to be had, or not preferred, the slip is to be prepared for planting by cutting it smoothly just below a bud, as this seems to be the most favorable point in many plants for the emission of roots. Some plants will throw out radicles at any point indifferently along the internodes or merithallus. The preference for heel-cuttings depends upon the fact, that near the base of the annual shoot there are always a great number of buds, many of which, however, being imperfectly developed, are inconspicuous, but though dormant, they seem to favor the emission of rootlets. Cuttings may be made to grow if taken at any period of their development, but when green and soft, they require particular conditions of heat and moisture in the soil, and atmosphere, that are only under the control of the professional gardener. They are usually taken in the dormant state, because they are then susceptible of being made to grow under the ordinary conditions of out-door gardening. If cut early in the season, on the approach of autumn, after the wood-growth has been perfected, they may be planted at once with good prospect of success, or they may be put into the soil, out of doors, in the cellar, or in a cold frame or pit, and a very important step in the progress of their growth will commence at once. The leafless sticks are not dead, and whenever the temperature will admit of the quiet interchange of fluids among their cells, this curious function will go on, and will be accompanied by the development or generation of new cells that soon cover the cut surfaces, constituting what the gardeners call the callus. This is the first step toward growth, and it most readily occurs when the earth is warmer than the air; hence the value of fall planting, whether of trees or of cuttings, if done before the earth has been chilled, and hence also, the importance of bottom heat in artificial propagation. If on the contrary the air be warm and the ground cold, the buds are often stimulated to burst forth, before the rootlets can have started. The expanding foliage which so delights the tyro in propagation, offers an extended surface for evaporation, the contained juices of the cutting itself are soon exhausted, no adequate supply is furnished, and the hopeful plant soon withers, or damps off, and dies.13 The cutting, like the seed, must have "first the root, then the blade." The length of time that is allowed for cuttings to prepare for rooting, if they are designed for spring planting, should be as great as possible, and the circumstances under which they are kept should be such as to favor the development of the cells, so that roots may form freely with the breaking of the buds, if not before.

Root-cuttings should be made in the spring, just before the usual period of the bursting of the buds in the plant to be propagated. The tendency to develop buds appears to be then most active. Gentle bottom heat, though not essential, is still very desirable, and will conduce to the success of the operation. Some plants are best propagated by this means, and those too, which never naturally produce suckers, may often be successfully grown by sections of the roots. All plants do not equally admit of propagation by division as cuttings, some woody tissues refusing to emit roots under almost any circumstances.

Nobody thinks of propagating the stone fruits, such as the cherry, plum, peach, or apricot, by attempting to plant cuttings, and yet some of these will emit roots very freely, as we may often observe when the shoots or trimmings are used as supports for plants in the green-house. The plum tree is exceedingly apt to form new roots when planted too deeply, and upon this fact depends the success or failure of the finer varieties when worked upon certain varieties of the wild stock. If the young trees are earthed up in the nursery, and set rather deeply in the orchard, they will soon establish a good set of roots of their own, emitted above the junction of the scion and stock, which is very preferable to the imperfect union and consequent enlargement that often results from using uncongenial stocks. The raspberry and blackberry do not grow so well from cuttings of the wood, which is always biennial in this genus, as they do from root-cuttings.

In some parts of the country, peaches are mainly produced, or the favorite varieties are multiplied, by planting the sprouts that come from the base of the trunk of the trees; these have little or no roots when taken off with the mattock, but they soon establish themselves and make good trees, bearing fruit like their parents, in soils and climate that are well adapted to this fruit.

Refined and scientific horticulture has been extensively applied to the multiplication of the grape, which is now produced in immense numbers, from single eyes, or buds. Formerly our vineyards were formed by planting long cuttings at once in the field in the stations to be occupied by the vines, or by setting them first in a nursery, whence they were transplanted to the vineyard, when one or two years old. Only the most refractory kinds, which would not grow readily in the field, or such as were yet rare, were propagated from cuttings, by using the single eye and artificial bottom heat. Now, however, the appliances of our propagators are called upon for the production of grape-vines by the million, and they find it advisable to multiply all the varieties in this manner. The propagation of the grape by using single eyes affords the most beautiful illustration of the subject of the individuality of buds, and though denounced by some as an unnatural, steam-forcing process, it is really an evidence of the advance of horticulture, since every step is supported by a philosophical reason, and the whole process, to be successful, is dependent upon the application to practice of well established scientific truths.

Fig. 1.—FRENCH AND COMMON MODES OF SETTING CUTTINGS.

It has already been stated that the first effect of cell-growth upon a cutting, is the production of a callus. This callus may form upon any cut surface, or even where the bark has been abraded. It is the first effort of nature to repair an injury by the reproduction of new parts; it is most generally found at the base of the cutting, but under favorable circumstances, it will be seen also at the upper end of the shoot if this has been placed in contact with the earth. Cuttings will sometimes be set up-side down, when we find the callus upon the smaller end, and roots will be emitted from that portion whence we should have expected to see the branches issue. Upon this fact, and to multiply the chances of living, has been based the French method, as it is called, or that of inserting both ends of the cuttings. The common mode, (fig. 1), is to set the cuttings in a slanting direction in the ground, so placed that the upper eye or bud only shall reach the surface. Formerly there was a preference for long cuttings, and these were often made eighteen inches or more in length. The practice with most of our cultivators has been modified in this particular, and they have reduced the length of the slips to six and eight inches, so as to have in grape wood about three or four eyes. Some have gone still further, and use but two, even for out-door planting of the grape, and some have been very successful when using but a single joint. The Germans have advocated longer cuttings, upon the theory that there was a retroaction in the pith of the internodes and in all the buds of the cutting, upon the lower point, enabling it to push roots more strongly from a long than from a short cutting. This theory has for its support the fact, that there is in such a cutting a larger amount of organizable matter to be developed into the new parts to be produced, and certainly, if neglected, short cuttings will be very apt to suffer from drought, but in practice, it is found that the short cutting plants have better roots, which are near the surface, and even those plants, grown from single eyes, are better burnished than long cuttings produced upon the old plan, which placed the roots deep in the soil.

Fig. 2.—ONE-EYE CUTTINGS OF THE GRAPE.

There are various methods of preparing the single-eye cuttings, some of which are represented in fig. 2.

Among our cultivated fruits there is but a limited number that need to be propagated by cuttings, though, where it becomes necessary, many of them may be grown in this manner, to which procedure there are no serious objections, though there are some of a theoretical nature. The currant and the gooseberry are increased almost exclusively from cuttings, they strike root very readily, and are multiplied to any extent; their seeds are sown only to produce new varieties. The grape is propagated very extensively by cuttings; the slips are often planted in the field and in the stations where the vines are wanted for the vineyard; but some varieties are so unsatisfactory in their results, that other more elaborate and scientific means must be taken for their propagation. Among the larger fruits, those constituting our trees, we do not depend upon cuttings, except in the quince, which is not only grown for its fruit, but is also largely produced as a stock for the dwarfed pear, and is extensively propagated from cuttings. The Paradise apple, a dwarf stock, is multiplied in the same way. Pears and apples may be grown from cuttings, but this plan is not pursued with them to any extent. Those that are root-grafted, or budded very low, especially the pear on quince stocks, will often produce roots if favorably situated, but there is a great difference in varieties, some rarely produce a root, while others are very prone to do it; from observations of this fact, a new phase of dwarf-pear culture has been inaugurated.

Suckers.—One of the simplest methods of multiplying varieties consists of increasing and encouraging the suckers thrown up by the roots; these are separated and set out for trees. We have been told by some physiologists that there was an absolute difference in structure between the root and the stem, that they could not be substituted the one for the other; and yet the oft quoted marvel of the tree which was planted upside down, and which produced flowers and leaves from its roots, while its branches emitted fibres, and became true roots, is familiar to every one. Here, as in other cases, our teachers have led us into error by attempting to trace analogy with animal anatomy and physiology, and by directing our attention to the circulation of plants, as though they, like the higher animals, possessed true arterial and venous currents of circulating fluids. The cell circulation is quite a different affair, and can be conducted in either direction, as every gardener knows who has ever layered a plant, or set a cutting upside down. So with the roots—they are but downward extensions of the stem; under ordinary circumstances they have no need for buds, but these may be, and often are developed, when the necessity for their presence arises. Buds do exist on roots, especially upon those that are horizontal and near the surface, and from them freely spring suckers, which are as much parts of the parent tree as its branches, and may be planted with entire certainty of obtaining the same fruit, just as the twigs when used as cuttings, or scions, when grafted, will produce similar results.

Whole orchards are planted, in some sections of the country, with the suckers from old trees; apples, pears, plums, and even peaches, as well as raspberries and blackberries, are multiplied in this primitive way. There are some varieties of apples that have been so propagated for half a century, and extended for hundreds of miles in this way by the pioneer emigrants, without ever having been grafted, until their merits have at length accidentally become known to the Pomological Societies and nurserymen, when the propagation of them by grafting soon supercedes the more primitive method. Sucker trees are objected to upon the grounds that they are not healthy and thrifty, that they do not have good roots. Inherent disease of the parent tree will of course be transmitted with its other peculiarities, but I cannot imagine that this would be any more likely to occur in a sucker than in a layer, or cutting, or graft. As to the roots, they may be more developed upon one side than another in the young tree, and this state of things may continue in the adult; we often observe the same condition in the stumps of the monarchs of our forests, which were never suspected in the day of their glory and pride of having such a fault. But such a condition of roots is not essential to the sucker, which may be made to have as fine a system of lateral roots, and as evenly and regularly distributed as those of a seedling tree. Another objection to this mode of propagation has much truth and some force; that is, that suckers are very apt to produce suckers again. This is particularly the case with the Morello cherry, which is a favorite stock, upon which to work many of the choice varieties. As an offset to this it may be urged, that the small fibrous roots, which are supposed to conduce to early fruitfulness, abound in trees propagated by this means, and this may be the reason why the fruit trees that have been thus multiplied, are very generally remarkable for their precocious fruiting. Some of the apples that have been long increased in this manner, bear so early, and so bountifully, as to prevent them from ever forming very large trees; they often have a stunted appearance, and not infrequently present a peculiar inequality upon the bark, portions being swollen or enlarged like warts—from which, in some cases, it is easy to force out shoots or sprouts; they are indeed true gemmules like those of the old olive trees, and like them might be used for the propagation of the variety; a similar condition, no doubt, exists in the roots, whence the tendency to sucker. The common Morello cherry; the Damson; the Chickasas, and other varieties of plum; the blackberry, and many raspberries, are multiplied almost exclusively in a similar manner.