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
