“It is for us, by our intelligence and labor, to work our way out of the difficulty; upon us it is enjoined to put into practice the noble creed, God helps those who help themselves.
“Thus from the earliest times it has been man’s study to select from the countless forms of vegetation at his disposal those that best lend themselves to improvement. The greater number of species have remained useless to us, but others, predestined no doubt, and created especially with a view to man’s needs, have responded to our efforts and acquired through cultivation qualities of prime importance, since our sustenance depends on them. Nevertheless the improvement attained is not so radical that we can count on its permanence if our vigilance relaxes. The plant always tends to revert to its primitive state. For example, let the gardener leave the headed cabbage to itself without fertilizing, watering, or cultivating it; let him leave the seeds to germinate by chance wherever the wind blows them, and the cabbage will quickly part with its compact head of white leaves and resume the loose green leaves of its wild ancestors. In like manner the vine, set free from man’s constant attention, will degenerate into the little-esteemed wild species that haunts our hedge-rows and yields a scant harvest that will not, all together, be worth a single bunch of cultivated grapes. The pear-tree, if neglected, will again [[163]]be found on the outskirts of our woods, once more bristling with long sharp thorns and bearing under-sized and extremely unpalatable fruit. Under like conditions the plum-tree and the cherry-tree will bear nothing but stones covered with a sour skin. In short, all the riches of our orchards will in similar circumstances undergo such deterioration as to be worthless to us.
“This reversion to the wild state occurs even under cultivation and in spite of efforts to prevent it when seed is used for propagating the plant. Suppose the seeds from an excellent pear are put into the ground. Well, the trees that spring from those seeds will bear for the most part only mediocre or poor, even very poor, pears. Another planting is made with the pits of the second generation, and the result shows still further decline. Thus if the experiment is continued with seeds taken each time from the immediately preceding generation, the fruit, becoming smaller and smaller, bitterer and harder, will at last return to the sorry wild pear of the thicket.
“One more example. What flower equals the rose in nobleness of carriage, in perfume and brilliant coloring? Suppose we plant the seeds of this superb flower; its descendants will turn out to be miserable bushes, nothing but wild roses like those of our hedges. But we need not be surprised at this. The noble plant had the wild rose for ancestor, and in trying to propagate it by its seed we have simply caused it to resume its native characteristics. [[164]]
“With some plants, let us note in conclusion, the improvement attained by cultivation is more stable and persists even when the seed is used for purposes of propagation; but this persistence is only on the express condition that our vigilance shall not relax. All plants, if left to themselves and propagated by seed, revert to the primitive state after a certain number of generations in which the characteristics imposed by human skill and care gradually disappear.” [[165]]
CHAPTER XXXIV
DIFFERENT WAYS OF PROPAGATING
“Since our fruit-trees and ornamental plants, if propagated by seed, revert sooner or later to the wild type, how can they be propagated without risk of degeneration? This must be done by means of the buds instead of the seeds. Buds or branches of a plant or tree must be transplanted from one stock to another; this is called grafting; or they may be planted directly in the soil by processes known as layering and slipping. These are invaluable methods, since they enable us to stabilize in the plant the improvements attained after long years of labor, and thus to profit by these improvements, which we owe to our predecessors, instead of beginning all over again a course of training that would demand far more than a single life-time.
“Layering, slipping, and grafting insure the faithful reproduction of all the qualities of the parent stock. As are the fruit, flowers, foliage of this parent stock which has furnished the buds or slips for transplanting, so will be the fruit, flowers, foliage of the resulting plant or tree. Nothing will be added to the qualities we wish to perpetuate, but on the other hand nothing will be subtracted. To the double flowers of the original from which came the [[166]]layer, the slip, or the graft, will correspond the double flowers of the plant developing from this layer, slip, or graft: the same shade of coloring will be reproduced, and the fruit will have the same size, savor, and sweetness. The slightest peculiarity which, for unknown reasons, appears in a plant grown from the seed, and which sometimes is found only on a single branch, as the indented outline of the leaves or the variegation of the blossoms, is reproduced with minute accuracy if the graft, slip, or layer is taken from the branch having this modification. By this means horticulture is daily enriching itself with double flowers or a new shade, or with fruit remarkable for its size, its early or late ripening, its juicy flesh, its more pronounced aroma. Without the help of graft and slip these fortunate accidents, occurring but once and no one knows how, would lead to no further profit after the death of the plant thus favored by chance; and horticulture would find itself compelled to repeat over and over again its attempts to bring about improvements which, almost as soon as effected, would invariably be lost for want of means to fix them and render them permanent.