Annuals and Biennials

A garden can be quickly filled with color by using annuals and biennials. These plants flower longer than many others and are ideal for filling gaps in a border.

Almost any patch of soil can be transformed into a blaze of color in a matter of weeks by planting nursery-grown annuals, or in two or three months with the plants you grow from direct-sown seeds.

Annuals are plants that grow, flower, produce seeds, and die in one growing season. The most popular kinds provide a longer-lasting display than perennials or bulbs, and they are invaluable for starting a new garden quickly. They can also be used to supply bright accents among shrubs or perennials, under trees, and in containers. Many of these plants provide excellent cut flowers as well.

Most annuals are inexpensive, easy to grow, and available in a broad range of colors and heights.

Plants that are similar in their general effect are biennials. They are started from seeds one year; they flower the next; and then they die.

In mild climates, however, some of the plants grown as annuals may survive the winter (they actually are tender perennials), and some biennials can be grown as annuals.

Annuals are classified in some books and catalogs, and on some seed packets, according to the British system, which divides them into two groups -- hardy and half-hardy. Hardy annuals, which tolerate cold weather, can be sown earlier than halfhardy annuals. This terminology often proves more confusing than helpful, however, because it does not apply to all areas of North America. Therefore, it is not used in this book.

The quickest and easiest way to enjoy flowers in the garden is to purchase young annuals or biennials in plant form in spring (also in autumn in the South) and set them directly in the garden. A wide choice of plants is available, but seeds, especially those offered in catalogs, provide an even greater diversity.

Seeds can be given an extra early start (especially in cold regions) by sowing them in a protected and controlled environment. This is almost a necessity for very fine seeds, such as those of the wax begonia; for seeds that need high temperatures to germinate, such as those of the impatiens; and for those plants that are slow to bloom from seeds, such as the vinca, petunia, and ageratum. Seeds can be started indoors if sufficient light and proper temperature are provided (see p. 193), or outdoors if a cold frame or hotbed that protects them from the elements can be located conveniently.

Seeds can also be sown directly outdoors where they are to flower. This is a popular and practical method for plants that bloom quickly, as well as for those that have large seeds (see p. 191).

Biennials, although fewer in number than the annuals or perennials, have some of the showiest garden flowers. Particularly popular are sweet William, Canterbury bell, foxglove, hollyhock, and pansy. They are usually sown in the late spring or early summer outdoors in a protected location.

When biennial seedlings are large enough to handle, they can be transplanted in rows to grow until late summer. By then they should be sturdy enough for transplantation to permanent positions or to spend the winter in a cold frame.

Many annuals and biennials have been garden favorites for centuries. A worthwhile advance in recent years has been the development of the F1, first generation, and the F2, second generation, hybrids (the F stands for filial). They are the result of selecting and inbreeding different parent lines of the same plant to get the most desirable characteristics and then cross-pollinating the plants to combine the best characteristics of each.

Several generations of this kind of breeding are required to produce plants of the desired quality. Some home gardeners may be deterred by the relatively high price of the seeds, especially since seeds saved from such hybrid plants will not produce plants of equal vigor or identical color the next year.

But the first generation of flowers grown from F1 hybrid seeds will demonstrate such superiority to the less expensive types that they are well worth the added cost. These hybrids offer clearer colors, more vigor, larger size, greater weather and disease resistance, and better, more uniform growth habits than their forebears.

F2 hybrids are the results of the hybridizers' attempts to improve the quality without the high cost of the F1 method. This is achieved by selffertilizing the F1's. In some cases it has worked. Generally, the F2 hybrids are an improvement on standard seeds, though not so spectacular as the F1's. Most seed catalogs do not mention the designations, but the difference in the price is usually an indication that the most expensive seeds are F1 hybrids or a new variety.

Selecting varieties from a catalog or seed rack can be confusing. In an attempt to simplify the choice, All-America Selections, founded in 1932, began growing new varieties submitted by hybridizers in official test gardens throughout the continent. Those awarded the highest number of points are designated as the All-America Selections, and every seed packet of those varieties is so labeled. The buyer can be assured that these varieties have proven to be superior to other plants under varied climatic and soil conditions.

Among most recent All-Americas are petunia 'Opera Supreme Pink Morn', a ground cover that flowers profusely; celosia 'Fresh Look Gold', free-branching and weather-tolerant; dianthus 'Supra Purple', long-flowering and heat-tolerant; cleome 'Sparkler Blush', with pink flowers that turn white with age; gaillardia 'Arizona Sun', with dark red flowers with petals tipped in yellow on a spreading plant; and zinnia 'Magellan Coral', with fully double flowers on a 12-inch plant. Other All- Americas are indicated by an asterisk on the chart beginning on page 197.

The above is an excerpt from the book The All-New Illustrated Guide to Gardening: Planning - Selection - Propagation - Organic Solutions by Edited by Fern Marshall Bradley and Trevor Cole. The above excerpt is a digitally scanned reproduction of text from print. Although this excerpt has been proofread, occasional errors may appear due to the scanning process. Please refer to the finished book for accuracy.

Copyright © 2009 Fern Marshall Bradley and Trevor Cole, editors of The All-New Illustrated Guide to Gardening: Planning - Selection - Propagation - Organic Solutions