Horticulture Principles and Practices

SUMMARY
Bedding plants are largely annual plants that are grown in beds. Whereas vegetable
bedding plants are grown for food, ornamental bedding plants are grown for aesthetic
reasons in the landscape. These plants are generally small in size. Flower beds should
be well drained and exposed to sunlight. Plants selected for use should be adapted to
the environment. Further, one should also consider the adult height, habit or form,
color, blooming habit, water and light needs, and general care required. Bedding
plants may be direct seeded or transplanted. Garden plants can be designed along certain
themes such as flower color, fragrance, or species (e.g., grass garden). Annual
gardens, which may include perennial species, generally require a degree of involvement
by the grower.
17.5 CHOOSING A GROUND COVER
Even though in the broadest sense any plant that spreads its foliage over the soil can be
called a ground cover, operationally the term is reserved for low, spreading plants
(less than 2 feet or 60 centimeters tall). This group of plants includes shrubs (e.g., dwarf
yew, creeping juniper, and dwarf azalea), vines (e.g., English ivy), perennials (e.g., lily of
the valley and twining strawberry), and grasses. Some species such as daylilies
(Hemerocallis spp.) are clump forming, and others such as ajuga (Ajuga reptaris) are
rhizomatous or stoloniferous.
Ground covers are used in a variety of ways. For example, they may be used to
reduce soil erosion on steep slopes; cover rocky and rough areas that are difficult to mow;
cover up areas under trees that are poorly lit; hide unattractive parts of the landscape; or
enhance the aesthetic value of the landscape by their attractive form, foliage, and flowers.
These plants generally have the capacity to grow in a manner as to blanket the ground
and frequently are also quick spreading. They do not require the regular maintenance
needed by some landscape plants.
Ground covers should be chosen to meet certain conditions:
Ground Cover
A low-growing plant that
spreads and forms a
matlike growth over an
area.
1. The hardiness zone. Unless the selections are adapted to the local climate, they
will not perform to their full capacity. Like other plants, some species are adapted
to cool climates and others prefer hot and dry climates. Some plants such as
hostas are adapted to a wide variety of climates.
2. The site characteristics. A good site analysis is needed to find out the specific
problems and how to select a ground cover to solve them. This analysis often
includes a soil test to determine the nutritional status of the soil in the area. If an
area in the landscape is bare, it might be due to a number of factors, such as
shade, shallow soil, low nutrients, improper pH, and others. The soil may be
sandy and drain too quickly or clay and hold too much water. The soil may have
an adequate amount of nutrients to support growth but a pH that does not make
the nutrients available to plants.
Table 17–4 provides some suggestions of plants to grow in shady conditions
such as under trees. Junipers and cinquefoil (Potentilla fruticola) perform well if the
area is a dry hillside of poor fertility. Table 17–5 lists some species adapted to steep
and rocky slopes. One hard-to-manage area in the landscape is the wet patch that will
not support a lawn. For such spots, possible choices include the creeping Jenny
(Lysimachia spp.), certain ferns, blue flag (Iris versicolor), and Japanese primrose
(Primula japonica).
3. Special effects. Ground covers are used for more than protection of bare ground
in the landscape. Some species have qualities to make them appropriate for use as
a focal point in the landscape. Apart from green foliage, ground covers can be
used for specific roles in the landscape. Ground covers with attractive colors
17.5 Choosing a Ground Cover 519