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Horticulture Principles and Practices

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(a)<br />

(b)<br />

FIGURE 2–22<br />

(Source: George Acquaah)<br />

Cole crops, represented by (a) broccoli (Brassica oleracea var. botrytis) <strong>and</strong> (b) cabbage (Brassica oleracea).<br />

2.4.1 HERBACEOUS ORNAMENTAL PLANTS<br />

Herbaceous plants are nonwoody. Many horticultural plants, especially those grown<br />

indoors, are nonwoody. They have a wide variety of uses in l<strong>and</strong>scapes as well. They may<br />

be classified in various ways.<br />

1. Growth cycle<br />

a. Annuals. Annual ornamentals are planted each season. Flowering annuals<br />

are prominent in the l<strong>and</strong>scape in favorable seasons, providing most of<br />

the color (Figure 2–23). Versatile l<strong>and</strong>scape plants can be used to fill in<br />

gaps, provide color in bulb beds after the bulbs have bloomed, <strong>and</strong> create<br />

colorful flower beds, hanging baskets (flowers grown in containers <strong>and</strong><br />

hung), <strong>and</strong> cut flowers (flowers grown <strong>and</strong> cut for use). Examples include<br />

petunia (Petunia spp.), zinnia (Zinnia elegans), <strong>and</strong> marigold (Tagetes<br />

spp.).<br />

b. Biennials. Biennial ornamentals are vegetative in their first year of growth<br />

<strong>and</strong> bloom in the next season. Examples are foxglove (Digitalis spp.) <strong>and</strong><br />

hollyhock.<br />

c. Perennials. Since perennials live for a long time in the l<strong>and</strong>scape, locating<br />

them requires a great deal of thought <strong>and</strong> planning. Perennials may be<br />

flowering or nonflowering.<br />

d. Flowering. Flowering perennials may be planted in flower beds in the fall<br />

season to provide early blooms, after which annuals may be planted.<br />

Examples are geranium (Geranium spp.), lily (Lilium spp.), <strong>and</strong> tulip<br />

(Tulipa spp.).<br />

e. Foliage. Foliage, or nonflowering, perennials are popular for indoor use in<br />

houses <strong>and</strong> offices as potted plants (Figure 2–24). Examples are coleus<br />

(Coleus blumei), sansevieria (Sansevieria spp.), <strong>and</strong> dumbcane<br />

(Dieffenbachia).<br />

2. Other operational classifications. Herbaceous plants may be used in a variety of<br />

other ways, both indoors <strong>and</strong> outdoors.<br />

a. Bedding plants. Bedding plants are annual plants raised for planting<br />

outdoors in flower beds. They are usually started from seed indoors in the<br />

off-season <strong>and</strong> transplanted later in the growing season. Examples include<br />

petunia (Petunia spp.), zinnia (Zinnia elegans), pansy (Viola tricolor), <strong>and</strong><br />

marigold (Tagetes spp.).<br />

2.4 Classification of Ornamental Plants 53

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