CHAPTER XIV.

OF TRAINING.

TRAINING is one of the most artificial operations that gardeners are acquainted with, its object being to place a plant in a condition to which it could never arrive under ordinary circumstances. It is so nearly connected with the art of pruning, that the French speak of both under the common name of la taille. The practice of it forms one of the most complicated parts of horticulture, each species of tree demanding a method peculiar to itself; but the principles on which training depends are few and simple.

Those who desire to understand the routine of training must refer to their garden library. In all works devoted to the art of gardening, full instructions are given for the management of every kind of tree in common cultivation. From Miller's Dictionary up to Mackintosh's very useful Book of the Garden we find the most minute instructions how to train a tree; there is wall-training and espalier-training, pyramidal-training and balloon-training, dwarf-training and standard-training, pillartraining, horizontal-training, zigzag-training, and a host of other devices which ingenious persons have invented. Some are necessary, some useful, some fanciful. In matters horticultural there are martinets as well as in matters military; and many a gardener practically falls into the error of supposing that the goose step, a tight jacket, leather stock, and pipe clay, make the soldier. He measures the angles of a tree, pinions its limbs, drills its branches by inexorable rules, "cuts hard in," "lays in close," and then believes he has exhausted skill. The tree looks well perhaps, but a small matter makes it ill, limb

422

THE OBJECTS OF TRAINING

after limb dies away, fruit does not set, and all its spruceness ends in rags and tatters. This comes of neglect of first principles. Not that a gardener should undervalue in the smallest degree the rules which long experience has established; quite the contrary. It is because it is observed without intelligence, and without a thought to first principles, that mere routine, however excellent, is apt to lead to failure. And it may be asserted with perfect truth that in training fruittrees, it is better to understand principles and to be ignorant of rules of practice, than to be familiar with the latter and unacquainted with the former. In this place principles only have to be adverted to.

It is probable that the intention of the first gardener who trained a tree was to gain some advantage of climate, by availing himself of a wall or other screen; and this is still one of our greatest objects; partly with a view to guard the flowers in spring from cold, and especially cold winds, partly to expose the leaves and fruit to a hotter temperature than would otherwise be gained, and in some measure to ripen wood with more certainty.

That training a tree over the face of a wall will protect the blossoms from cold must be apparent, when we consider the severe effect of excessive evaporation upon the tender parts; a merely low temperature will produce but little comparative injury in a still air, because the more essential parts of the flower are very much guarded by the bracts, calyx, and petals, which overlie them, and, moreover, because radiation will be intercepted by the branches themselves placed one above the other, so that none but the uppermost branches which radiate into space will feel its full effects; but, when a cold wind is constantly passing through the branches and among the flowers, the perspiration, against which no sufficient guard is provided by nature, becomes so rapid as to increase the amount of cold considerably, besides abstracting more aqueous matter than a plant can safely part with. To prevent this being one of the great objects of training trees, it is inconceivable how any one should have recommended such devices as those mentioned in the Horticultural Transactions, ii. Appendix, p. 8., of

TO GAIN A HIGHER TEMPERATURE.

423

training trees upon a horizontal plane; the only effect of which would be to expose a tree as much as possible to the effect of that radiation which it is the very purpose of training to guard against.

The actual temperature to which a tree trained upon a wall facing the sun is exposed is much higher than that of the surrounding air, not only because it receives a larger amount of the direct solar rays, but because of the heat received by the surrounding earth, reflected from it and absorbed by the wall itself. Under such circumstances the secretions of the plant are more fully elaborated than in a more shady and colder situation; and, by aid of the greater heat and dryness in front of a south wall, the period of maturity is much advanced. In this way we succeed in procuring a Mediterranean or Persian summer in these northern latitudes. When the excellence of fruit depends upon its sweetness, the quality is exceedingly improved by such an exposure to the sun; for it is found that the quantity of sugar elaborated in a fruit is obtained by an alteration of the gummy, mucilaginous, and gelatinous matters previously formed in it, and the quantity of those matters will be in proportion to the amount of light to which the tree, if healthy, has been exposed. Hence the greater sweetness of Plums, Pears, &c., raised on walls from those grown on standards. It has been already stated that an increase of heat has been sought for on walls by blackening them; and we are assured in the Horticultural Transactions (iii. 330) that, in the cultivation of the Grape, this has been attended with the best effects. But, unless when trees are young, the wall ought to be covered with foliage during summer, and the blackened surface would scarcely act; and in the spring the expansion of the flowers would be hastened by it, which is no advantage in cold late springs, because of the greater liability of early flowers to perish from cold. That a blackened surface does produce a beneficial effect upon trees trained over it is, however, probable, although not by hastening the maturation of fruit; it is by raising the temperature of the wall in autumn when the leaves are falling, and the darkened surface becomes. uncovered, that the advantages are perceived by a better com

424

TO DIMINISH THE RATE OF GROWTH

pletion of the process of growth, the result of which is the ripening the wood. This is, indeed, the view taken of it by Mr. Harrison, who found the practice necessary, in order to obtain crops of Pears in late seasons at Wortley, in Yorkshire (see Hort. Trans., iii. 330, and vi. 453). It hardly need be added that the effect of blackening will be in proportion to the thinness of the training, and vice versâ.

Another object of training is, to place a tree in such a state of constraint that its juices are unable to circulate freely, the result of which is exactly that already assigned to the process of ringing (see p. 370). If a stem is trained erect it is more vigorous than if placed in any other position, and its tendency to bear leaves rather than flowers is increased; in proportion as it deviates from the perpendicular is its vigour diminished. For instance, if a stem is headed back, and only two opposite buds are allowed to grow, they continue to push equally, so long as their relation to the perpendicular is the same; but, if one is bent towards a horizontal direction, and the other allowed to remain, the growth of the former is immediately checked; let the depression be increased, the weakness of the branch increases proportionally; and this may be carried on till the branch perishes by a process of abstracting food analogous to starvation in animals. In training, this fact is of the utmost value in enabling the gardener to regulate the symmetry of a tree, and to cause one part to balance another exactly, which is one of the first objects the trainer has to attain. Whenever one branch or one side of a trained tree becomes stronger than another, the difference increases till the larger succeeds in starving the former. It however by no means follows that, because out of two contiguous branches, one growing erect and the other forced into a downward direction, the latter may die, that if all branches are trained downwards any will die. On the contrary, a general inversion of their natural position is of so little consequence to their healthiness, that no effect seems in general to be produced beyond that of causing a slow circulation, and the formation of flowers. Hence the directing of branches downwards is one of the commonest and most successful contrivances employed by gardeners to

BY TRAINING DOWNWARDS.

425

render plants fruitful. Mr. Knight was the first to recommend the practice, in the following account of his recovery of an old and worthless Pear-tree.

"An old St. Germain Pear-tree, of the spurious kind, had been trained in the fan form, against a north-west wall in my garden, and the central branches, as usually happens in old trees thus trained, had long reached the top of the wall, and had become wholly unproductive. The other branches afforded but very little fruit, and that never acquiring maturity was consequently of no value; so that it was necessary to change the variety, as well as to render the tree productive. To attain these purposes, every branch which did not want at least twenty degrees of being perpendicular was taken out at its base; and the spurs upon every other branch, which I intended to retain, were taken off closely with the saw and chisel. Into these branches, at their subdivisions, grafts were inserted at different distances from the root, and some so near the extremities of the branches, that the tree extended as widely in the autumn after it was grafted, as it did in the preceding year. The grafts were also so disposed, that every part of the space the tree previously covered was equally well supplied with young wood.

"As soon, in the succeeding summer, as the young shoots had attained sufficient length, they were trained almost perpendicularly downwards, between the larger branches and the wall, to which they were nailed. The most perpendicular remaining branch upon each side was grafted about four feet below the top of the wall, which is twelve feet high; and the young shoots, which the grafts upon these afforded, were trained inwards, and bent down to occupy the space from which the old central branches had been taken away; and therefore very little vacant space remained any where in the end of the first autumn. A few blossoms, but not any fruit, were produced by several of the grafts in the succeeding spring; but in the following year, and subsequently, I have had abundant crops, equally dispersed over every part of the tree; and I have scarcely ever seen such an exuberance of blossom as this tree presents in the present spring." (Hort. Trans., ii. 78.)