PRUNING (from prune, from OF. proignier, proyncr, prorigner, Fr. prorigncr, to prune, from OF., Fr. prorin, vine, from Lat. propago, sucker, from prop(' go re, to propagate, from pro, before, for pangere, pegnynai, to fasten). The removing of any part of a plant, either root, stem, or branch, to discourage growth in one direction and turn the energies of the plant in another. It is considered an artificial operation, but nature is a constant and very severe pruner, as is shown by the long, slender, limbless boles of many forest trees. When plants are taken from their natural environment and the forces which regulate their habits, pruning becomes a necessity. In this work the gardener must be guided by the well-known laws of plant growth governing the healing of wounds and the balance of parts. At planting time the tops of trees must be pruned in order to establish a proper relation of top to root, which is always un avoidably reduced in the process of digging. This pruning is necessary also because the roots have no intimate connection with the soil by which the demands of the expanding leaves can be supplied with food and moisture; in fact, the demands of the top should be less than the root can meet in order that a too severe strain shall not be placed upon the organism. Pruning may be performed for the purpose of correcting the habit of growth. The head may be made high or low, compact or open, at will, almost regard less of the natural habits of the tree. In gen eral, however, the peculiar nature of the tree should be taken into account and the pruning made to conform as closely as possible to that form. Where fruit is the object sought the man ner of fruit production of the plant must be thor oughly understood. otherwise pruning may in duce wood growth at the expense of fruit pro duction. For instance, apples and pears bear fruits upon spurs; peaches, usually on the young branches (sometimes on spurs) of the previous season's wood; grapes, on wood of the current year produced from buds developed the year previous. In order, therefore, intelligently to prune any plant for fruit production, its fruiting habit must be carefully considered. Sometimes desired results are obtained by root pruning. or by cutting away a portion of the bearing wood. In the first ease fruit-bearing is induced, in the second the fruits are thinned or their number decreased. the food supply distributed to a less
correspondingly in creased in size. Pruning also admits light to the tree tops by removing superfluous brandies. thus making the fruits higher colored.
Besides these objects pruning is used to ehange the form of head ('heading in'). Whatever be the object. the operation should be performed in the manner least injurious to the plant. This in volves the method of removing the branch and the time of year the work should be done. In regard to the season for pruning little exact information can be given. As a rule apples. pears, and cher ries suffer least if pruned while in full vigor of growth. The wounds heal readily and there is less liability to loss of vitality than at other sea sons. The peach should be pruned lqirly and severely for wood growth, and late and lightly for fruit production; the same is also true of the grape. All pruning of the grape and peach should be confined to the resting period.
The manner of pruning so as not to lessen the vigor or shorten the life of the plant involves systematic annual pruning, by which the removal of large branches ean be avoided. All cuts should be made dose to and parallel with the main branch so as to pnunote the healing process. Large wounds must be covered with some preser vative or protective coating to prevent decay. The healing of a wound is avemnplished by the formation of a callous from the growing tissues. The process continues, and 1py the annual deposi tion of new material the wound is covered. A smooth cut will heal where a cult or hruise will decay. Trees orown upon walls or espaliers require great skill in pruning in order to hold them within bounds. and at the same time secure the maximum production of fruit or flowers. In grape-growing certain styles of pruning have been given special names—e.g. re newal, high renewal, Kniffem etc.
Ornamental trees are either pruned for the purpose of correcting the habit of growth, as the shortening of a leader in order to thicken the growth and wake the tree broader, or for the purpose of giving the plant a particular form, as is the case with hedge plants and with ever greens used in formal gardens.
Consult Bailey, The Pruning Book (New York. 1898), also numerous experiment station bulletins.