This section is from the book "The Gardener V2", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Many ways of training and pruning the Peach and Nectarine have been practised and recommended. French horticulturists especially have been very successful in training them in several ways characterised by regularity and neatness. The single cordon as well as the multiciple cordon systems are favourite modes of training in France. " Modifications partaking more or less of the French systems have been practised and recommended especially by Seymour in England. But the ordinary fan system of training is by far the most generally practised and liked. It is, especially under glass, the mode of training which the most successful forcers of the Peach have adopted, and it is that which I recommend. Many grand old examples of Peach-trees under glass are to be found in this country, which have all along been trained on the fan principle, and that are yet in fine bearing condition, being well furnished from top to bottom with young bearing wood. Taking a young tree (fig. 11 in May No.) which I have recommended for planting as the foundation of a fan-trained [tree, different cultivators who are most in favour of this system of training would deal differently with the ten young growths with which it is furnished.
Some would cut them all back again, to within five or six buds of their base; others would not shorten them at all, but would let them start into growth with as many young shoots as could be tied to the trellis without crowding them. What I have practised and would recommend is a mean between these two systems. The two centre shoots I would shorten back to half their length, the other eight shoots to be merely topped back to solid, well-ripened wood. The cutting somewhat closely back of the two centre ones makes it certain that two or three good strong growths will start from near their base to properly fill up the centre of the tree with leaders. Each of the other eight shoots should have all its buds removed by degrees, except one near the base, and one or two at equal distances between it and the leading bud, according to the length of the shoots, two buds to be left on the under side; if the shoots are long enough to have room for three on the upper side, the buds on the one side to alternate in position with those on the other side. These lateral growths with the leader are enough to lay a foundation for the future full-grown tree. The lateral growths should be allowed to grow without being stopped.
Should the leaders show signs of growing very vigorously, at the expense of the side growths, stop them whenever they show such a tendency. This will cause them to make lateral growths freely, and equally balance the growth of all the young shoots. This encouragement of lateral growths, especially on the young wood in the centre of the tree, gives sufficient to furnish the tree without having recourse to the undesirable practice of first allowing a few very strong leaders to monopolise the sap, and then to cut them down at the winter pruning. In this way much time is gained in covering a wall or trellis with bearing wood.
A young tree thus managed on what may be termed a mean between the extension and cutting-hard-back system, produces a comparatively large well-furnished tree the autumn after it is planted, and one which requires very little winter pruning before starting it into another year's growth, when the same principle should be applied, especially to the extremities of the tree. All the winter pruning that is necessary is simply to shorten back the young growths to thoroughly-ripened wood, and to remove any lateral growths, the presence of which would crowd the tree. There is, however, comparatively little difficulty in ripening the wood of young Peaches under glass with the command of fire-heat. By the second autumn after planting, the trees will cover the trellis to a very considerable extent.
After the trees have grown and covered the space allotted to each, the system of pruning must be directed so as to continually keep the whole tree regularly supplied with young fruit-bearing wood. With a view to this, of course the yearly removal of old wood in winter, and the laying in of a corresponding amount of young wood in summer, must be carefully attended to. Fig. 13 gives an idea of what I mean by this, and will serve to illustrate the pruning out of old wood and laying in the new. The shoots represented by the solid lines are those which bore fruit last summer, and those shown by the dotted lines, growing from, base of the fruit-bearing wood, are those laid in in summer to bear the following season. In pruning such a tree, the last year's wood, shown by the solid lines, is cut off close to the young wood which is to supply the next year's crop.
Some make a practice of cutting back the young bearing wood to two-thirds its length. I do not advocate this indiscriminately. When the shoots are long and not well ripened, and the buds consequently weak, they should be shortened back to where the wood is firm, and always to a strong wood-bud. Peach-trees in a healthy condition have their buds in clusters of three, a wood-bud in the centre, and a fruit-bud on each side of it; and to such a cluster of buds they should always be cut when cut at all.
Well-established trees that have borne heavy crops regularly, and especially those that have been forced early, generally make shorter and stronger growths, well studded with strong clusters of buds. In this case it is unadvisable to shorten them back at all. A watchful eye must always be kept on the lower portions of the tree, so that they are not allowed to get bare of young fruit-bearing growths. It need scarcely be said that, from the fact that it is the young wood that bears, the tendency is for it to be in greatest abundance at the top.
The best guarantee against trees becoming bare of young bearing wood at their lowest parts, is to annually cut back a few healthy young growths to 2 or 3 eyes, and allow as many of these to bud and grow as may be required to keep up the supply of young wood. This is an indispensable necessity, from the fact that portions of old wood have annually to be removed at the top of the tree. In practice, all other things being equal, there is little difficulty experienced in thus furnishing the lower portions of the tree with bearing wood. All cutting should be effected with a sharp thin knife; and whenever it becomes necessary to remove an old limb, the wound should be painted solidly over with white paint.
I have already referred to what is termed Seymour's system of training, from its having been first adopted at Carlton Hall in Yorkshire, by a gardener of that name. By this system a tree of great regularity and neatness is formed. It differs from the fan system of training in there being no lateral growths allowed on the lower sides of the leading branches. ' Figure 14 will illustrate this mode of training. "The first step in starting a newly-planted maiden tree upon Seymour's system, is to head the plant down to three eyes, each of which eyes will produce a shoot in summer; at pruning time head down the centre shoot of these to three eyes, to produce in the following summer three more shoots as before, leaving the side shoots always at full length. In spring all the buds on the lower sides of these side branches, and these from 9 to 12 inches asunder, are rubbed off, leaving those only which proceed from the upper side of the branch; when the young wood has extended to the length of 5 or 6 inches they are stopped, but the leading branches are not interfered with.
Every year will produce a side shoot on each side of the tree, and the laterals that proceed from them at the distance we have stated are at first laid in between them, but the following spring these are removed from the wall and trained up on the main side branches. By the autumn of the third year the number of laterals will be doubled on the two side branches first laid in, as a new lateral is sure to spring from the base of the one laid in the previous season, as well as one from its point. As to winter pruning in the fourth year, all the laterals of two years' growth, and which have already produced a crop of fruit, are to be removed entirely, and those of .the previous summer's formation are to be unfastened from the wall and laid upon the main leading side branches in the place of those cut out".
My objection to this otherwise neat and very systematic mode of training is, in the first place, that it takes a much longer time to cover a given space of trellis or wall than it requires to do so on the fan system, when the needless and objectionable close-cutting-back system is not adhered to. Then again, when any of the leading branches give way - no uncommon thing in Peach-trees - a great gap in the tree is created, which it takes longer to make up than when a gap takes place in fan training.
The time for pruning the Peach under glass must be regulated by the time that forcing is commenced. Generally speaking, it is best to defer pruning till the first signs of the swelling of the buds, especially in the case of inexperienced pruners, as then wood-buds' and fruit-buds are easily distinguished. This of course refers to the. shortening back of all young wood that requires it. D. T.