Horticulture Principles and Practices

15.8 OTHER FUNCTIONAL USES OF PLANTS
IN THE LANDSCAPE
15.8.1 PRIVACY FROM ADJOINING PROPERTY
No matter how good one’s neighbors, homeowners usually demand some privacy from
adjoining property. A fence may be installed as a divider. High-growing shrubs can be
planted to create a dividing wall. Plants behind bathroom and bedroom windows may be
selected to be aesthetically pleasing as well as adding privacy from neighbors.
15.8.2 CLIMATE MODERATION
Trees with large canopies provide shade and protection from the sun’s radiation
on hot days. At night, however, radiation from the soil is reduced, creating a
microenvironment under the canopy in which temperatures are more even. By planting
evergreen trees or shrubs close to west- or south-facing walls, a dead-air space can be
created between the “plant wall” and the wall of the house (Figure 15–14). This space
has insulation capability similar to the dead space deliberately created by some architects
in home design. The effect of this condition is that summer temperatures are moderated
and kept even. Ivy-covered concrete walls (or those covered by any other
climber) reduce the temperature of the wall relative to the bare wall when exposed to
full sunlight.
15.8.3 GLARE REDUCTION
A streetlight in front of a house may provide light in undesirable parts of the house.
Blinds may have to be pulled down at night. A tree can be located in the path of the
light rays to block or reduce the amount of light reaching the house (Figure 15–15).
Another light moderation strategy is to plant deciduous trees near the sunniest area of
the house to reduce light and provide shade. In winter, these plants shed their leaves,
allowing more light to reach the house through the bare canopy. To reduce glare
throughout the day as the sun’s position changes with the earth’s rotation, plants of
different heights may be planted in the path of the sun, the shortest plants nearest to
the sun.
FIGURE 15–14 Planting trees
close to the wall can create a
dead-air space for temperature
modification.
N
Dead-air space
496 Chapter 15 Principles of Landscaping