Horticulture Principles and Practices

Monocarp
A plant (e.g., bromeliad,
century plant) that lives for
many years but flowers
only once in a lifetime and
then dies, new plants arise
on the roots of the old
plant.
herbaceous perennials are turfgrasses such as Bermuda grass (Cynodon
dactylon) and flowers such as daylilies (Lilium spp.) and irises (Iris spp.).
Woody perennials may be vines, shrubs, or trees. These plants do not die back
in adverse seasons but usually suspend active growth. Although some perennials may
flower in the first year of planting, woody perennials flower only when they become
adult plants. This stage may be attained within a few years or even after 100 years.
Woody perennials may be categorized into two types:
a. Evergreen. Evergreen perennials maintain green leaves year-round. Some
leaves may be lost, but not all at one time. Examples of evergreen perennials
are citrus (Citrus spp.) and pine (Pinus spp.).
b. Deciduous. Deciduous plants shed their leaves at the same time during one
of the seasons of the year (dry, cold). New leaves are developed from
dormant buds upon the return of favorable growing conditions. Examples
of deciduous perennials are oak (Quercus spp.) and elm (Ulmus spp.).
It should be mentioned that intermediate conditions occur in which some
plants do not lose all of their leaves (semideciduous).
4. Monocarp. Monocarps are characterized by repeated, long vegetative cycles that
may go on for many years without entering the reproductive phase. Once flowering
occurs, the plant dies. A well-known example is the century plant (Agave spp.). More
common examples are the bromeliads. When these plants bloom, the top parts die,
and new plants arise from the root system of the old plant.
2.3.2 KINDS OF STEMS
There are three general classes of horticultural plants based on stem type. However,
intermediates do occur between these classes.
1. Herbs. Herbs are plants with soft, nonwoody stems (Figure 2–4). They have primary
vegetative parts. Examples include corn (Zea mays), many potted plants, many annual
bedding plants, and many vegetables. In another usage, the term herbs is associated
with spices (plants that are aromatic or fragrant and used to flavor foods or beverages).
FIGURE 2–4 An example of an herb or
herbaceous plant. Stems can also be herbaceous.
(Source: George Acquaah)
FIGURE 2–5 A shrub showing the typical
multiple stems arising from the ground. (Source:
George Acquaah)
44 Chapter 2 Classifying and Naming Horticultural Plants