Horticulture Principles and Practices

7. Pruning can be used to create special effects. With pruning and training, plants
can be manipulated to produce unique shapes and forms in the landscape. Such
techniques include pollarding and coppicing.
568 Chapter 19 Pruning
19.2 OBJECTIVES OF PRUNING
Although the manner of pruning varies, the general objectives remain similar. All of the
objectives may not be required or accomplished in any one particular instance, since
pruning may be used for a specific purpose at a particular stage in the growth of a plant.
The four general purposes of pruning are plant sanitation, aesthetics, reproduction,
and physiology.
19.2.1 PLANT SANITATION
Pruning may be undertaken to remove plant parts that create an unsanitary condition.
Specific actions geared toward improved plant sanitation include the following:
1. Broken branches and dead tissue on plants provide surfaces on which
disease-causing organisms grow and thus jeopardize the health of plants.
Broken branches pose grave danger to people.
2. Diseased plant parts may be removed to prevent the spread of infection.
3. The plant may be cleaned by removing unsightly dried or dead parts.
4. The canopy can be opened up so that air can circulate freely and thereby reduce
humid conditions that predispose plants to disease.
5. An open canopy enables effective spraying by allowing pesticides to penetrate
the canopy.
6. Removal of excessive undergrowth not only keeps the landscape clean but also
reduces hazards from brush fires.
19.2.2 AESTHETIC OBJECTIVES
In ornamental horticulture, the visual appeal of plants is of paramount importance to
gardeners, especially if plants are in the landscape. Pruning is employed for shaping the
form of the plant. After determining the desired shape, branches are strategically
removed or their growth controlled to maintain the shape.
In formal gardens or on certain public grounds such as those found in zoological
or botanical gardens, certain plant species are grown, trained, and trimmed into
geometric figures or readily recognizable or abstract shapes. This art form is called
topiary.
Pruned plants can by themselves be attractive elements in the general landscape.
However, more pleasing components can be produced if the style of pruning takes into
account other elements in the landscape such as the architecture of the house, the terrain,
and artificial structures such as statues and fountains.
19.2.3 REPRODUCTIVE OBJECTIVES
Pruning may be undertaken to enhance the reproductive capacity of the plant in
several ways:
1. The canopy may be opened up by cutting out the branches in the center. This
allows light to penetrate the canopy for fruiting to occur on inner branches.
2. Fruiting may be regulated by encouraging the growth and development of
fruiting shoots while reducing nonreproductive shoots.
3. Pruning may be done to balance reproductive and vegetative growth for
optimal yield.