This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
Again, spring pruning is most convenient, because in summer we usually have our orchard land under cultivation, and by pruning then, the crops must be much injured by trampling them down, and by the branches thrown upon them. I am perfectly aware of future; and we shall have to write a good while longer, before men will be persuaded to plant for the future, at such present sacrifice as is involved in surrendering the entire income of their best and most convenient land, even for so long a period as is required in bringing an orchard into bearing.
The objections to early spring pruning are, that the wounds then made do not heal so readily as when the tree is in full process of growth. This is, perhaps, true, and may be admitted as a fact, without being practically entitled to much weight, because I think with us, vigorous trees seldom suffer any delay or failure in the healing of wounds made in pruning, at either season.
I have said that our grafting is all done in April. The old native trees are fast being changed to finer fruit, and thousands of stocks are grafted every spring. The work is often done carelessly. Limbs of two or more inches in diameter are cut off, the scions inserted, the grafting cement is spread on, and no further attention given to the matter. And yet it is very rare to see a stock dead, or imperfectly healed, even under the rudest treatment, and such being the fact, there can be little danger of injury from the cause referred to, in pruning with ordinary care at the season of grafting.
I have recently examined several orchards which have been uniformly pruned in April, and among the rest that of Freeye Dearborn, Esq., of this place. His trees are among the best within my knowledge. He informs me that he raised them from the seed, planted about twenty-six years ago; and set them where they now stand, nineteen years ago. He gathered one hundred and fifty barrels of the Baldwin, last year, from forty trees - being all the trees in one enclosure, which are old enough to be reckoned bearing trees. He has many others, principally of a younger growth. From one of the forty, he took nine barrels of fine fruit.
If we judge Mr. Dearborn by his fruits, we must concede that his principles cannot be far from correct. Upon examining his orchard with him, for the purpose, we could find no indication in any instance, that injury had resulted from pruning. There appeared no mark of disease or decay where the branches had been cut off, and yet Mr. Dearborn says he has pruned always in spring, and has never applied anything to the wounds, or even used a knife, after removing the limbs with a saw.
So much for the practice, and now let us see how the most rational theories correspond with these results. I shall attempt no scientific examination of the question by what power in nature the circulation of the sap is carried on. Some facts in regard to it, are obvious. We know that in the spring the sap rises from the roots to the branches. That it rises not by capillary attraction merely, and not, in the first instance, by any attracting power, exerted by or through the leaf-buds or branches, would seem to be true, because the sap flows in great quantities from the stumps of trees recently cut. Every boy in a sap-sugar country, has drunk from the top of a rock-maple stump, hollowed out to retain the up-rising sap. Whether as much sap flows from such a stump as could have been drawn from the tree, by tapping in the ordinary mode, I have no means of knowing. The pressure of the up-rising sap is, at its first flow, very great. In Gregory's Dictionary of Arts and Sciences, it is stated that by affixing tubes to the stumps of vines cut off at the rising of the sap it has been ascertained that the sap rises in the tubes thirty-five feet shire, may be found, under the title "Endosmose and Exosmose," a most interesting theory of the circulation of sap, which I should be glad to see entire in the Horticulturist, at some convenient season.
It rests upon some mysterious inherent tendency of gases and of liquids of different densities to commingle, a tendency which neither the power of gravitation, nor the intervention of any membrane, either animal or vegetable, if the cellular tissue of plants and the thin diaphragms that lie at intervals across the sap vessels may be so termed, can overcome. This tendency is so strong as to force liquids through a piece of bladder, as may readily be ascertained by experiment, in the manner pointed out by Dr. Jackson. The same principle, of the transmission of gaseous matters though membranes, has been applied to explain the chemical phenomena of respiration. Whether the fact that the sap rises and flows from the stump, where there is no liquid above to entice it upward, does not conflict somewhat with this theory, as applied to the circulation of the sap, may deserve consideration. But whatever be the principle of the motion, this "upward striving" of the sap occurs chiefly in spring. At least, at that season, it has a power greater than at any other. And it seems to be generally conceded, that it has then not only a peculiar impulse, but also a peculiar character or quality, and that the first flow of the sap is designed to promote the growth of wood.
If this be so, we should infer that wounds made before the force of this peculiar sap is spent, that is to say, before the growth of the wood, would heal more readily than those made afterwards.
At page 49 of your Jan. No., under the title "Fruitfulness Promoted by Late Pruning," in an extract from a French publication, may be found what seems a rational theory about pruning, which may be briefly stated thus. The growth which is made in early spring, is induced entirely by the sap in the roots. By diminishing the top previous to the rising of the sap, the remaining shoots receive the sap designed for the whole, and therefore make a more vigorous growth. The fertilizing sap which induces fruitfulness, is not formed until later, the leaves being the organs of its formation. By a late pruning so much of the vitality of the tree is wasted, as has gone into the growth of the branches removed. A late pruning promotes fruitfulness at the expense of the vigor of the tree, as it seems to be generally conceded that anything that checks the growth of the wood, as root-pruning and the like, tends to the formation of fruit buds, and the converse seems to be true, that great fruitfulness, by whatever means induced, checks the growth of wood.
That the removal of part of the top in early spring, promotes the growth of the remainder, seems evident from the rapid growth of scions, even when set in full grown trees; and probably no one will contend that the growth of wood is, in the same degree, increased by pruning in summer. It is a common, and doubtless correct idea with our farmers, that to kill bushes they should be cut in summer, and that if cut in winter or spring, the life principle is still left active in the root, and they will spring up anew. I have tried the experiment of heading-in young apple trees to promote their growth. I was aided in my first trial, by a drove of cattle, which in the spring of 1847, broke into my orchard and browsed off nearly the entire tops of thirty fine trees, of which part had been grown there one year, and part were set the previous autumn. Their mode of pruning was sufficiently through as they left most of their subjects no limb more than six inches long, but the tunity to observe the effect of heading-in young apple trees, and so smoothed matters over as well as possible with my pruning knife, and awaited the result.
Many of those trees made shoots four feet long the following season, and now they are of about the same size as those which escaped the operation.
I have since cut back every other one of forty trees, at the time of transplanting. My opinion is, that the growth is rather promoted than retarded by this process, but that the tree is disfigured, and requires far more subsequent attention to keep it in order. A curve, like that produced by budding, is made at the place where the twig is cut off, and often several shoots are thrown out in the place of the one removed, so that it is difficult to keep an open top, so desirable in an apple tree. I much prefer thinning the tops of apple trees, to shortening their leading shoots.
In thus suggesting my views, Mr. Editor, I wish distinctly to disclaim any attempt at originality. The various theories above stated, are by no means overlooked in your valuable treatise upon Fruits and Fruit-Trees. Several considerations must always modify the views of writers on this subject. My own experience has been only in a section of the country where the apple is a healthy tree, and little liable to disease or decay, from the wounds of the pruning knife, and where high manuring is necessary to obtain a sufficient growth. With a soil and climate of a different character, the same theories might lead to different conclusions. Even the reasons of convenience for spring pruning, which have been given, although almost imperative upon us, would have no force where the season is longer, and land more abundant and fertile. If my views seem heretical, I shall be happy to have them corrected. The true idea is, for each of your correspondents to speak out as he thinks. Upon this, as upon most other subjects, "error of opinion may safely be tolerated, where reason is left free to combat it."
In conclusion, perhaps a hint may not come amiss, from one who has at least followed a good example, that your correspondents affix their own names to their communications. Such friends of the cause as Jeffries, and "A Constant Reader," ought not to "hide their light under a bushel," by the use of fictitious signatures; and as to the beautiful "Wild Flower," (surely beautiful in spirit,) what right has she to date from "In the Bushes," and to keep her "local habitation and her name," a mystery. At all events, she gives a new interest to the Horticulturist, and your readers may flatter themselves that if she is, indeed, "born to blush unseen," she does not entirely "waste her sweetness on the desert air." With much respect, Henry F. French.
Exeter, N. H., April 10,1851.