Annuals are the work horse of the flower garden. They bloom from Spring through Fall - and because of Colorado's high light intensity, the colors of annuals are more vibrant than anywhere in the nation.
Good annuals for sunny locations: Geranium, marigolds, portulaca (moss rose), petunias, zinnias, verbena, daisy, dianthus, cosmos.
Good annuals for partial sun: Snapdragons, allysum, lobelia, pansies, salvia, vinca, wax begonia.
Good annuals for shade: Impatiens, coleus, tuberous begonias, mimulus, torenia, fuchsia.
Something new to try:
Schizanthus - multicolor orchid-like bloom with ferny foliage. Part sun.
Bacopa - brilliant white carpet of mini blooms, cascading style. Great for basket and container gardening. Full-sun to part sun.
Swan River Daisy (Brachyscome) - daisy like one inch flowers in blue or lavendar, attracts butterflies. Full sun to semi-shade.
Wave Petunias - pink or purple petunias appear profusely throughout the season, mostly used as groundcovers, baskets or garden beds. Full sun to part shade.