Annuals are useful for several reasons. With a little attention they grow well for most gardeners and provide almost instant color. Many are purchased in bud or bloom to begin flowering soon after planting. They continue to bloom until frosted in the fall. If this year's selections are not the best choices, they only need to be tolerated for one year. Next year change the color scheme or plant arrangement to a more satisfactory design. Well designed and selected plantings can be changed due to the large variety of annual types and colors.
The most impressive use of annuals is in large groups of one color. To mix colors, plant in small groups of one color. The least effective use is mixing the individual plants and colors.
Annuals give color to spring flowering bulb beds after the bulbs have finished blooming. Such beds are often unattractive while the bulb foliage is maturing and the annuals are too small to hide it. Most bulbs are planted deep enough so annuals may be planted over them. Where bulbs are shallow, plant spreading annuals around the grouping of bulbs. The bulbs will be covered eventually even though no annuals are actually planted over them.
Annuals are excellent in a garden for cut flowers. If the garden provides many cut flowers, few blossoms may remain in the garden. Include spike flowers as well as round individual flowers. Consider color compatibility between the flowers and the decor of rooms where the arrangements are to be displayed.