HOME GARDENS

Bay of Plenty Beacon, Volume 14, Issue 18, 29 July 1949, Page 6

HOME GARDENS

By the Horticultural Department Massey Agricultural College.

PRUNING OF TREES & SHRUBS Pruning is considered to be an art, and when one considers the reasons and methods behind this art it is obvious that there is more to it than meets the eye. If proper attention is paid to a young tree in the first two or three years if its life, subsequent pruning need be of only a minor nature, and not the removal of large limbs as is often the case. If the young tree is of the oak, ash, lime, or beech type, it will be necessary to train _ a single leader until it is about 20 feet high or more, and all side ! branches which are liable to rob the leader of its vigour should be removed. The tree can then be left to develop normally. With trees of a smaller nature, such as cherries and crab apples, a clean stem is not so important, but even a short trunk of, say, six or eight feet high, will add to the tree’s appearance. When encouraging one leader to become dominant it is a mistake to trim off all lateral branches at once as this induces rapid growth of the leader and tends towards spindliness. At the same time it greatly reduces the leaf sm-face of the plant, which condition is harmful at this stage. Therefore side branches should gradually be short- j ened back, and one or two of the bottom branches removed over a period of several years. Occasional- j ly a vigorous shoot may develop ! close to the leader and rival it. If the original leader leans to one side it may be an advantage to cut it ] out and let the second one take its place. It is always worth the time and trouble to protect even small wounds after pruning, as a slight bark injury is sufficient for the entry of disease spores. Maples are very susceptible to disease entering from a small wound. When pruning some deciduous ornamental trees in winter before full leaf development, there is often a tendency for many of' them to bleed freely, and this is difficult to check. This bleeding is ready sap flow. Classes of Flowering Shrubs The question of when, and how, to prune flowering shrubs revolves around two points; firstly, the time of flowering and, secondly, the type of wood upon which the flowers are borne. If these two points are known there is very little difficulty in judging how and what to prune. Garden shrubs will fall into one of the following classes:— (1) With shrubs that bear their flowers on the current season’s wood, i.e., the new wood, pruning may.be done in the winter or early spring, as these plants bear their flowers in summer ar autumn. Shoots of the previous year are pruned back to within several inches of the old wood, sufficient old wood being left to provide a good framework for the shrub. Examples of shrubs falling into this group are hydrangeas, Buddelia Day, idii, ceanothus, the Gloire d.e Versailles type, Philapelphus, and the latesummer and autumn-flowering spiraeas such as spiraeas jopanoca Anthony Waterer and spiraeas lindleyana. * (2) With those that flower on the wood produced during the previous sumer, and generally flower in the late winter, spring and early sum- . mer, pruning is best done immediately after flowering, as this gives the plant as much time as possible to form and ripen new wood, before the winter sets in. It is upon this new wood that next season’s flowers will be borne. (3) Shrubs that kower through the summer and bear their flowers on the wood produced during the previous growing season. Wjhen these shrubs are flowering they are also producing new wood upon which to flower the following summers so, if pruning were done after flowering,, much of the new wood might be cut away. These shrubs should therefore have the oldest I wood cut from the base in early ! autumn. ] (4) There is also the class of J shrub which grows up vigoorus j young growths direct from the base. If the old wood produces the best I flowers, these young growths should ( be cut out. If the young growths I produce the best flowers or coloured I stems, they should be cut hard each year to encourage .new shoots. (5) Some shrubs produce their j flowers on wood more than two | years old, often on short spurs. Very j little pruning is needed in this j class, but the young growths can be. cut ack to within two or three inches of the old wood in the winter. Evergreens and conifers are usually only thined out, and kept trimmed to shape.