Horticulture Principles and Practices

4. Pruning may be done to reduce the number of fruiting branches per plant
(thinning out) in order to increase fruit size and quality.
5. Generally, proper pruning enables a fruit-bearing tree to produce higher-quality
fruits over a longer period. Flowering plants also produce bigger flowers over
a longer period of the plant’s life when pruned.
6. Properly pruned trees have good fruit distribution throughout the plant canopy
(not only at the edges) and bear fruit of good size, color, texture, and sugar
content.
7. Pruning allows the gardener easier access to fruits during harvesting.
19.2.4 PHYSIOLOGICAL OBJECTIVES
Pruning, if not done judiciously, may have adverse physiological consequences on plant
growth and development. However, pruning may be employed to manipulate plant
physiology in a variety of ways to enhance the performance of the plant:
1. Pruning roots before transplanting reduces the chance of transplanting shock.
2. Pruning shoot tips in species with apical dominance (e.g., apple, pear, and cherry)
induces lateral branching and thereby prevents the tree from growing straight
without sufficient branching.
3. Pruning deciduous species during the dormant period in winter conserves the
plant’s stored food for use in spring for vigorous new growth.
4. Severe pruning may have a dwarfing effect on a plant by reducing total vegetative
growth.
5. Older plants may be rejuvenated by pruning to stimulate new growth.
Apart from these four general purposes of pruning, the procedure may be
employed on specific occasions for practical reasons. For example, when plants grow
bigger and exhibit destructive tendencies such as roots cracking pavements or foundations
of buildings, roots clogging sewage pipes, and branches destroying the roof or
touching utility cables, the affected plant parts need to be pruned to contain the plant in
the available space.
19.3 PLANT RESPONSE TO PRUNING
Removing vegetative parts of plants affects certain plant physiological processes and
subsequently growth and development. The two basic plant responses to pruning are
described in the following sections.
19.3.1 INTERFERENCE WITH APICAL DOMINANCE
As previously stated, apical dominance of terminal buds suppresses the growth of lateral
buds. The removal of terminal buds removes this inhibitory effect, allowing lateral buds
to grow. In certain plants, gardeners deliberately remove terminal buds (pinching or pinch
pruning) to encourage lateral bud growth so that plants look fuller and more appealing.
The vertical shoots that arise on the upper side of branches, called water sprouts are an
example of a plant response to interference with the process of apical dominance.
Pinch Pruning
Breaking by hand of the
terminal bud.
19.3.2 GROWTH STIMULATION
A physiological balance exists between the top and bottom growths of plants. Removing
parts of the top growth upsets this balance. Plants respond with a burst of new growth,
especially just below the cut. In spite of the new growth, pruned plants do not exceed the
size of the plant before pruning. This dwarfing effect on plant size occurs because
the amount of new growth does not match what was removed in addition to what would
19.3 Plant Response to Pruning 569